题干
.
Cars play an important role in modern life , but they ____ also cause many problems like air pollution.
Cars play an important role in modern life , but they ____ also cause many problems like air pollution.
A：should
B：ca
C：must
D：will
答案(点此获取答案解析）
B
和
的图象的对称中心完全相同，若
，则
的取值范围是 （ ）