My dictionary ________．I have looked for it everywhere but still ________ it．

has lost; don’t find

was missing; don’t find

has lost; haven’t found

was missing; haven’t found

The little girl was ________ when she saw the ________ scene．

frightened; frightened

frightening; frightened

frightened; frightening

frightening; frightening

No matter how frequently ________, the works of Beethoven still attract people all over the world．

performed

performing

to be performed

being performed

See the flags on top of the building．That was ________ we did this morning．

when

which

where

what

It was not until she got home ________ Jennifer realized she had lost her keys．

when

that

where

before

Although medical science ________ control over several dangerous diseases, what worries us is that some of them are returning．

achieved

has achieved

will achieve

had achieved

You have failed two tests．You’d better start working harder, ________ you won’t pass the course．

and

so

but

or

When I met him the other day, it was the first time we ________ each other since we were at school．

saw

had seen

were seeing

have seen

It was on the farm ________ he spent his childhood ________ he learned how to grow vegetables．

where; that

which; when

that; that

which; which

Not only ________ to us the importance of doing the work but they also told us the best way to do it．

did they explain

they explained

they explain

had they explained