entists are trying to developa special material, _______ they will make use of in space.

ho _________English for 20 years inEnglish, now has been appointed headmaster of our school．

Our hometown develops so fast.—That’s true. Great changes ________ there in the past few years.

When will you come to see me, Dad? —I will go to see you when you _____the training course.[ ]

ung man couldnt afford a new car. _______, he bought a used one.