练习：
1. What effect does nevirapine have?
A It is a broad-spectrum antibiotic and kills all kinds of bacteria.
B It is an antiviral preparation and kills all kinds of viruses.
C It prevents the transmission of the AIDS virus and protects one from heart attack.
D It may prevent passing HIV infection from mothers on to their newborns during delivery.
2. Why does HIV resistance against nevirapine build very quickly even when the drug is used alone just once?
A Because the drug is not strong enough to kill all of the HIV in the body.
B Because there may not be a susceptibility test before using the drug.
C Because other drugs are not present to kill the virus particles that survive nevirapine.
D Because there are too many mutations of HIV for nevirapine to deal with.
3. When may a woman start her nevirapine-based treatment if she gets the single dose of nevirapine at delivery ?
A She may start nevirapine-based treatment soon after her delivery.
B She may start nevirapine-based treatment within six months after her delivery.
C She has to wait at least six months after that nevirapine exposure.
D She may wait several years so as to achieve the best effect.
4. We may learn from this passage that HIV resistance against nevirapine
A lasts only for about a half year and fades quickly.
B will last forever in a woman who took nevirapine.
C is a terrible drug that must be banned at once.
D is a problem too difficult to be solved.
5. Generally speaking, the author's attitude towards the use of nevirapine is
A negative
B positive
C uncertain
D doubtful
