常用的防冻液为乙二醇型防冻液。
A. 对
B. 错
The robber told him that he had better keep silent ______ he wanted to get into trouble
A. if
B. unless
C. otherwise
D. whether
I’d get it for you ______ I could remember who last borrowed the book.
A. on condition that
B. now that
C. except that
D. considering that
We are worried about our son because no one is aware ______ he has gone.
A. the place
B. of where
C. about the place
D. where