As the intelligence of robots increases to match ________ of humans，we may use them to expand our frontiers.
#15222
A
it
B
that
C
which
D
the
推荐题目
—Is there any vaccine(疫苗) against H1N1 flu that can be used on humans?—No, but scientists are working to develop ________ .
#16397
A
that
B
it
C
one
D
so
The traffic on the main streets has a longer green signal than______ on the small ones.
#15095
A
one
B
this
C
that
D
it
Health experts believe that even a little exercise is better than______ at all.
#56598
A
none
B
little
C
no one
D
few