We can't live _____ air. [ ]
A. without
B. with
C. to
D. out
答案：A
When the book was first _________, it was immediately well received by readers. [ ]
A. brought up
B. brought down
C. brought about
D. brought out
电容两端的电压和电流的相位关系是：同相、反相、电压超前电流90°、电流超前电压90°？
