Every year, we plant many trees on _______ side of the road to make our city more beautiful.
| A．both | B．all | C．each | D．neither |
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 |