—Many people talk about "Didi". I really wonder ______.
—You call to order a taxi through it on your mobile phone easily.
A. how can I use them
B. who uses them most
C. what they are used for
Students can’t be made ____________ all day.
| A．study | B．to study |
| C．studying | D．of study |
You know great changes _____________ in our school in the past ten years.
| A．have been taken place | B．took place |
| C．have taken place | D．were taken place |
Paul doesn’t know _________ about his problems.
| A．how to talk to | B．who to talk |
| C．where to talk to | D．who to talk to |
--Who _______ the Harry Potter series________ ? -- J.K.Rowling.
| A．did, be written | B．was, written |
| C．was, written by | D．did, be written by |
We know that about seventy percent _____ the earth _____ covered by water.
| A．/; is | B．of; are |
| C．of; is | D．about; are |