1.We should use cloth bags instead of plastic bags.
➝Cloth bags__________________________
2.They will know the result next week.
➝The result ________________________
3.We can____ thind evelopes
A.use
B.used
C.using
D.reuse
4. We are delighted___ you are interested in protecting the enviroment
A.what
B.why
C.what
D.when