正确的操作是实验成功的保证。下列操作正确的是[ ]
A.
B.
C.
D.
答案:D
Have you _____ your father recently?
No. He doesn't often write to me. [ ]
A. heard about
B. heard of
C. heard from
D. got from
– How many ____ are there in a year?
–Four
A. weeks B. hours C. seasons