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
—When are you leaving __________ Beijing?—Tomorrow. I’m arriving in Beijing at 3:00.
#48180
A
不填
B
for
C
to
D
from
His father is __________ engineer and he works __________ research.
#49406
A
an, on
B
an, with
C
the , on
D
a, with