When trees are cut down, there is nothing to hold the soil ________ on the hillside．

take place

out of place

in place

in place of

On his way home, he suddenly heard his name ________．

calling

called

to call

call

There is plenty of rain in the southeast, ________ there is little in the northwest．

because

therefore

while

as

Don't leave the water ________ while you brush your teeth．

run

running

being run

to run

We ________ arrive at six．But I'm sorry we are late．

should

were supposed to

must

ought to

Only ________ to use this reading room．Students have another room on the second floor．

are the teachers allowed

are allowed the teachers

the teachers are allowed

the teachers allowed

Having rejected

Rejected

Being rejected

To be rejected

Think about it carefully and you will find this math problem is so easy ________．

being solved

to solve

solving

to be solved

No sooner ________ the office than ________ his computer to check his e-mails．

had he entered; did he started

had he entered; he started

he had entered;did he started

he had entered; he started

Anyone who was interested in our adventure club can ________ its membership．

apply for

fight for

call on

wait on