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
Don’t lose heart. It won’t be long ___________ you catch up with others.
#94551
A
since
B
until
C
as
D
before
_______ we know, hurricane is _______ to come.
#94948
A
As soon as; possible
B
As long as; probable
C
As far as; likely
D
As well as; perhaps
Scientists say it may be five or six years _____ it is possible to test this medicine to human patients.
#92420
A
since
B
after
C
before
D
when
The city of Nanchong has grown so fast that it’s at least what it used to be.
#93468
A
five times the size of
B
five times the size as large as
C
five times larger
D
five times size as
---You look unhappy, what’s happening, my son? ---I’m wondering how long it’ll be________ we come to China again.
#92424
A
since
B
when
C
before
D
after