_______ the manager, you’d better call _______ his company．

Calling at; on

Calling on; at

To call on; at

To call at; on

Great changes _______ in our city in the past twenty years．

have been taken place

have taken place

took place

were taken place

He said he would rather not _______ it right now．

doing

to do

do

to be doing

These photos reminded him of the places _______ he visited last year．

which

that

不填

all above

Environmental experts are those who devote _______ to _______ nature and environment．

them; protecting

their; protect

themselves; to protect

themselves; protecting

_______ unexpected advice they have given us!

What

What an

How

How an

To many teenagers the cellphone is not only _______ useful tool but also _______ way to have fun and be cool．

the; the

an; the

a; a

a; 不填

Kentucky is the state _______ Lincoln was born．

which

there

in that

where

Alice trusts you, only you can _______ her to give up the foolish idea．

suggest

attract

advise

persuade

Every four years athletes from all over the world _______ medals in the Olympic Games．

compete

compete for

fight with

fight against