25型客车水位显示器电源的额定电压为()V。
A.12
B.24
C.36
D.48
参考答案:D
—Jenny took the 8: 00 bus to Guangzhou this morning.
—Really? She ________ the 9:00 train. It's much more comfortable and safer to travel by train.
A.could have taken
B.should take
C.must have taken
D.can take
选择与全面、典型与综合的关系是什么?