There were several messages from people, most of _________ I didn't know, on my answering machine when I got home．

those

which

whom

them

_________ under the tree was a charming girl aged about seventeen or eighteen．

Sat

Sitting

To sit

Sit

It puzzles him why people here are so interested in what his job is．He _________ that question frequently．

has asked

gets asked

is asking

was asked

We _________ last night, but we went to the concert instead．

must have studied

might study

should have studied

would study

The _________ you need for an activity or task are the qualities and skills that you need to be able to do it．

qualification

composition

collection

satisfaction

A motorcycle _________ by electric power, which does good to the environment, becomes quite popular in our city．

driven

being driven

to be driven

is driven

They won’t buy any new clothes because they _________ money for a new car．

save

were saving

are saving

have saved

With a lot of difficult problems _________, the manager felt worried all the time．

settled

to be settled

settling

to settle

Our bad living habits will destroy the earth．Only by changing _________ we live can we save the earth．

that

what

how

where

Charlie Chaplin is considered _________ a great contribution to the film industry．

to make

making

to have made

having made