Talk to your teacher and you will get help ________ you have a problem.
A. unless B. if
C. until D. so
We have friends to help us fight against pollution, and trees are one of ________.
A. themselves B. they
C. their D. them
Now, people regard drinking tea ________ a culture more than a habit.
A. as B. by C. of D. with
Our mother earth gives us ________ we need in our daily life.
A. nobody B. nothing
C. everybody D. everything
Three bridges ________ over the river five years ago.
A. built B. build
C. were built D. are built
We are happy to see our city is developing ________ these years than before.
A. quickly B. the most quickly
C. very quickly D. more quickly