Части речи. Наречие.
Части речи. Наречия.
Общее значение: признаковость (признак действия или признак признака).
Классификация: по своей семантике наречия подразделяются на следующие группы:
- наречия времени: afterwards, already, at once, eventually, immediately, lately, now, presently, soon, suddenly, then, when, yesterday, yet…
- наречия частотности: always, constantly, hardly ever, never, occasionally, often, seldom, sometimes, twice…
- наречия места или направления: abroad, ashore, backwards, below, downstairs, everywhere, here, inside, outside, to and fro…
- наречия образа действия: badly, clearly, deeply, fast, how, quickly, sideways, sincerely, somehow, well, willingly…
- интенсификаторы: completely, enough, extremely, highly, much, nearly, perfectly, pretty, quite, rather, really, so, somewhat, terribly, too, unusually, very…
- наречия c низкой степенью интенсификации: a bit, slightly, almost, barely, moderately, more or less, nearly, partly, scarcely, somewhat, sufficiently…
- наречия с общим значением ‘точка зрения’: economically, morally, politically, scientifically…
- наречия отношения: admittedly, allegedly, correctly, cleverly, luckily, preferably, obviously, reasonably…
- конъюнктивные (союзные) наречия: above all, accordingly, alternatively, as a result, at any rate, besides, instead, on the contrary…
Грамматические категории: английские наречия по большей части не изменяются, но некоторые способны к образованию степеней сравнения (по тем же правилам, что и имена прилагательные)
Характерные синтаксические позиции: наречия модифицируют отдельные слова, фразы и предложения. Когда они модифицируют глагол, они могут служить обстоятельством времени, частотности, места, образа действия или степени. Когда они модифицируют прилагательные, они служат обстоятельствами интенсификации. Также бывают непозиционными: выступают в качестве союза или вводного слова.
Морфологические особенности: многие наречия образованы от прилагательных при помощи суффикса –ly (happy-happily; beautiful-beautifully; suitable-suitably)
Задание 1 Ознакомьтесь с текстом, найдите в нем наречия и определите из синтаксические функции.
Hepatitis: An inflammation of the liver characterized by diffuse or patchy necrosis affecting all acini.
The major causes of hepatitis are specific hepatitis viruses, alcohol (see Ch. 40), and drugs (see Ch. 43). Less common causes include other viruses (eg, infectious mononucleosis, yellow fever, cytomegalovirus) and leptospirosis. Parasitic infections (eg, schistosomiasis, malaria, amebiasis) affect the liver but do not cause true hepatitis. Pyogenic infections and abscesses are also generally considered to be separate problems. Involvement of the liver with TB and other granulomatous infiltrations is sometimes called granulomatous hepatitis (see Ch. 45), but the clinical, biochemical, and histologic features differ from those of diffuse hepatitis.
Various systemic infections and other illnesses may produce small focal areas of hepatic necrosis and inflammation. This nonspecific reactive hepatitis causes minor liver function abnormalities but is usually asymptomatic.
Noninfectious liver inflammation and some hepatic infections are described under their specific topic headings and are summarized in Table 42-1.
Diffuse liver inflammation caused by specific hepatotropic viruses.
(See also Neonatal Hepatitis B Virus Infection under Neonatal Infections in Ch. 260.)
At least six specific viruses appear to be responsible (Table 42-2). Liver infections caused by other viruses (eg, Epstein-Barr, yellow fever, cytomegalovirus) are considered separate disorders and generally are not termed acute viral hepatitis.
Hepatitis A virus (HAV) is a single-stranded RNA picornavirus. Viral antigen is found in serum, stool, and liver only during acute infection. IgM antibody appears early in the disease but diminishes within several weeks, followed by the development of protective IgG antibody (anti-HA), which persists usually for life. Thus IgM antibody is a marker of acute infection, whereas IgG anti-HA merely indicates previous exposure to HAV and immunity to recurrent infection. HAV invariably disappears after acute infection; unlike both hepatitis B and C viruses, HAV has no known chronic carrier state and plays no role in the production of chronic hepatitis or cirrhosis.
Hepatitis B virus (HBV) is the most thoroughly characterized and complex etiologic agent. The infective Dane particle consists of a viral core plus an outer surface coat. The core contains circular double-stranded DNA and DNA polymerase, and it replicates within the nuclei of infected hepatocytes. Surface coat is added in the cytoplasm and, for unknown reasons, is produced in great excess; it can be detected in serum by immunologic means as hepatitis B surface antigen (HBsAg), formerly
- HBsAg is associated with the viral surface coat; its presence in serum is usually the first evidence of acute HBV infection and implies infectivity of the blood. (Several antigenic subtypes are of epidemiologic interest but little clinical significance.) HBsAg characteristically appears during the incubation period, usually 1 to 6 wk before clinical or biochemical illness develops, and disappears during convalescence. The corresponding protective antibody (anti-HBs) appears weeks or months later, after clinical recovery, and usually persists for life; thus, its detection indicates past HBV infection and relative immunity. In up to 10% of patients, HBsAg persists after acute infection, and anti-HBs does not develop; these patients usually develop chronic hepatitis or become asymptomatic carriers of the virus.
- Core antigen (HBcAg) is associated with the viral core. It can be found in infected liver cells but is not detectable in serum except by special techniques that disrupt the Dane particle. Antibody to HBcAg (anti-HBc) generally appears at the onset of clinical illness; thereafter, titers gradually diminish, usually for years or life. Its presence with anti-HBs is not significant beyond indicating previous HBV infection. It is also regularly found in chronic HBsAg carriers, who do not mount an anti-HBs response. In chronic infection, anti-HBc is mainly of the IgG class, whereas in acute infection, IgM anti-HBc predominates. Occasionally, IgM anti-HBc is the only marker of recent HBV infection, reflecting a "window" between disappearance of HBsAg and appearance of anti-HBs.
- The e antigen (HBeAg) appears to be a peptide derived from the viral core. Found only in HBsAg-positive serum, HbeAg tends to parallel the production of viral DNA polymerase. Its presence, therefore, reflects more active viral replication and is generally associated with greater infectivity of the blood and a greater likelihood of progression to chronic liver disease. In contrast, presence of the corresponding antibody (anti-HBe) points to relatively lower infectivity and usually portends a benign outcome.
Hepatitis D virus (HDV), or delta agent, is a unique, defective RNA virus that can replicate only in the presence of HBV, never alone. It occurs as a co-infection with acute hepatitis B or as a superinfection in established chronic hepatitis B. Infected hepatocytes contain delta particles coated by HBsAg. Prevalence of HDV varies widely geographically, with endemic pockets in several countries. Drug addicts are at relatively high risk, but HDV (unlike HBV) has not widely permeated the homosexual community. Clinically, HDV infection is typically manifested by unusually severe acute hepatitis B (up to 50% of cases of fulminant hepatitis B are associated with HDV co-infection), an acute exacerbation in chronic HBV carriers (superinfection), or a relatively aggressive course of chronic hepatitis B.
Hepatitis C virus (HCV) is now known to cause most cases of what was previously termed non-A, non-B (NANB) hepatitis. This single-stranded, flavivirus-like RNA agent causes the vast majority of posttransfusion and sporadic NANB hepatitis. Multiple HCV subtypes exist with varying amino acid sequences (genotypes); these subtypes vary geographically and play a role in disease virulence. HCV can also alter its amino acid pattern over time in an infected person (quasispecies); this propensity hampers vaccine development.
Most cases of hepatitis C are subclinical, even in the acute stage. The infection has a much higher rate of chronicity (about 75%) than hepatitis B. Thus, hepatitis C is often uncovered by the serendipitous detection of anti-HCV in apparently healthy persons.
Hepatitis E virus (HEV) is an RNA agent responsible for outbreaks of epidemic acute hepatitis, often waterborne. Outbreaks have occurred exclusively in developing countries. The infection may be severe, especially in pregnant women, but chronicity does not occur and there is no known chronic carrier state.
Hepatitis G virus (HGV) is a new flavivirus-like agent that has been detected in a few cases of non-A-E hepatitis. HGV can apparently be transmitted by blood and may be responsible for some cases of chronic hepatitis. The role of HGV and other unidentified agents in cases of unexplained hepatitis remains unclear.