— What do you think of the program?
— Great! It has made important contributions to ________ our school clean and tidy.
A.keep B.have kept C.keeping
His grandma saw the changes ________.
A.himself B.herself C.hers
________ he is busy, ________ he is glad to take part in volunteer activities.
A.Though; but B.Though; however C./; but
So far, the population ________ about two percent.
A.has increased by B.has increased to C.increased by
The traffic in the city __________ be terrible, but now it has improved a lot. I think you will __________ it soon.
A.used to; used to B.get used to; used to C.used to; get used to
The ________population has caused many serious problems.
A.large B.more C.much
