If there are ______ trees, the air in our city will be _______ cleaner.

A．less, more    B．more, more

C．more, much    D．much, more

You shouldn't ____ the boy's mistakes．

A．laugh at    B．smile    C．laugh     D．laugh down

______our teacher is ill, ______ he still comes to our class to teach us.

A. Though; but         B. Though; /

C. Although; but        D. But  though

The teacher said that the earth ______ around the sun.

A. moves           B. move         C. moved         D. had moved

I felt it hard to keep up with my classmates. But whenever I want to__   __ ，my teacher always encourages me to work harder.

A. go on             B. run away

C. give up           D. give back

_________great weather it is today!

A. How     B. How a     C. What     D. What a

They found         very difficult to learn Japanese well.

A. that             B. this       C. myself         D. it

I don't know the way, she doesn't know,

A. too          B. also         C. nor          D. either

The box is __________heavy for me _________carry.

A．to, too       B．so , that

C．such , that    D．too , to

He often saw his mother __________ clothes .

A. washed B. washes C. wash D. washing