______ difficult it is, he is determined to ______ the experiment.

_______no doubt that a green campus plays an important role in the growth of students, both physically and mentally.

My parents and I _____ going _____ vacation next week. [ ]

There is no furniture in our new house. Maybe the wooden box can be used _____ a table. [ ]

The roof of the house needs repairing.It’s raining now,you’d better get something to ________ rain drops.