It never _____ humans until the mid1990s that some animals can be cloned.
#92718
A
occur
B
is occurred
C
occurred to
D
occurred
推荐题目
Find ways to praise your children often, you’ll find they will open their hearts to you.
#92075
A
till
B
or
C
and
D
but
How long do you think it was ______ he got home in such bad weather?
#92115
A
when
B
since
C
that
D
before
How long ______ we take part in the college entrance examination?
#92168
A
is it since
B
will it be before
C
is it when
D
will it be since
Could you drive me to the bookstore at noon if________?
#92091
A
it's convenient of you
B
you are convenient
C
it's convenient to you
D
you will be convenient
The new machine is supposed to be the solution to all our production problems, but"____".
#93175
A
Practice makes perfect
B
The proof of the pudding is in the eating
C
Many hands make light work
D
I think, therefore I am