Years ago we didn't know this, but recent science ______ that people who don't sleep well soon get ill.
#104011
A
showed
B
has shown
C
will show
D
is showing
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I know Mr Brown； we ＿＿＿＿＿＿ to each other at an international conference.
#104666
A
are introduced
B
have been introduced
C
were introduced
D
had been introduced
. ---- Do you know our hometown at all? ---- No, this is the first time I ____ here.
#102925
A
was
B
have been
C
came
D
am coming
Susan decided not to work on the program at home because she didn’t want her mother to know what she _____.
#103156
A
has done
B
had done
C
was doing
D
is doing
I am so tired，for I ________ English for 2 hours.
#99761
A
is studying
B
have been studying
C
was studying
D
had been studying
By the time he realizes he into a trap, it’ll be too late for him to do anything about it.
#103233
A
walks
B
walked
C
has walked
D
had walked