Sound travels ______ air ______ a speed of about 340 metres per second.
#47987
A
over; in
B
through; at
C
by; at
D
through; over
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Mr. Lee arrived      Beijing       May 6th      about 12:00 .
#46095
A
in; on; at
B
at; on; on
C
for; in; at
D
in; in; at
—How does Tom go to school?—He goes to school ________.
#48537
A
by bus
B
on his bus
C
take a bus
D
by a bus