Sound travels ______ air ______ a speed of about 340 metres per second.
#47987
A
over; in
B
through; at
C
by; at
D
through; over
推荐题目
—It’s not easy _________Mrs White to persuade（劝说）her husband to stop smoking. He never listens to others.—Really? It’s stubborn ____________ him.
#48110
A
of; of
B
for; of
C
for; for
D
of; for
—What do you usually do on the weekend?—I usually help Scott his Chinese.
#48229
A
with
B
of
C
for
D
to