问题

The scientists ________ on the new medicine for two years. They will succeed in no time.
A:work
B:are working
C:have worked
D:will work
B:are working
C:have worked
D:will work
正确答案是:
同类题型
Where are you going ___________ the holiday? [ ]
Things made by hand are usually more expensive than _ produced in factories.
_____do you sleep every night? —Six to eight hours.[ ]
What’s _______mane?– ________ am Millie.
Learning country’s language is a better way of knowing ________ culture behind it.