This year is the 49th Earth Day and I think we should people not to too many trees．（ ）
| A． |
call on； cut down |
| B． |
call at； cut up |
| C． |
call in； cut off |
______ October 1，we will celebrate the seventieth birthday of the People's Republic of China．（ ）
A．OnB．InC．At
There are only big trees on one side of the street，different flowers lie on ______．（ ）
A．otherB．anotherC．the other
Life is like a story． What matters is not how long it is but______．（ ）
A．how good it isB．how good is it
C．what good it is
China is getting better at making hi﹣tech products ______ can be bought in all parts of the world．（ ）
A．whoB．whichC．what
Of the two physics problems， Martha just finished ______ one．（ ）
A．the most difficultB．the least difficult
C．the less difficult