问题
选择题
Private cars are required to take turns off roads one out of five weekdays ____the traffic pressure.
A.relieve(缓解)
B.to relieve
C.relieving
D.relieved
答案
A
考察不定式用法。本句中的不定式做目的状语,指为了缓解交通压力,私家车轮流上路。故A正确。