恒压源和恒流源实际上都是不存在的。
A. 对
B. 错
____office is much smaller than ____.
A. Ours ; yours
B. Our ; yours
C. Theirs ; our
D. yours; ours
A friend of ____ came to see ____ yesterday.
A. his ; his
B. he ; him
C. his ; him
D. him; his
Who teaches ___ French?
A. we
B. our
C. us
D. ours