China ______ a lot of people moving to urban areas in the last 20 years. However, many migrants  left their families behind.
#100122
A
saw
B
sees
C
has seen
D
had seen
推荐题目
Now then, children, it’s right time you ______.
#102530
A
wash and dress
B
are washed and dressed
C
will wash and dress
D
were washed and dressed
 The problem with people in Africa ____that the more is given and the more ______.
#103689
A
is; is needed
B
are; is needed
C
is; they need it
D
are; they need it
 Visitors ________ not to touch the exhibits.
#99747
A
will request
B
are requested
C
are requesting
D
request
With the development of high technology, more and more new things ______ in the past years.
#100055
A
discovered
B
have discovered
C
had been discovered
D
have been discovered