. —Why didn’t you response to their greeting?  —Sorry. I ______they ______ to me.
#102318
A
don’t realize; are waving
B
don’t realize; were waving
C
didn’t realize; were waving
D
didn’t realize; are waving
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Great changes ________ in that school. It is no longer _______ it was 20 years ago.
#103299
A
have taken place, that
B
have been taken place, what
C
have taken place, what
D
took place, the place what
—What’s that terrible noise?—The neighbors      for a party. 
#100709
A
have prepared
B
are preparing
C
prepare
D
will prepare
With the development of science,more new technology      to the fields of IT.
#104546
A
has introduced
B
is being introduced
C
is introduced
D
was introduced
 Hurry up! The train _____. You know it______ at 8:30 am.
#100211
A
leaves; leaves
B
is leaving; leaves
C
leaves; is leaving
D
is leaving; is leaving