_____ in the regulations that you should not tell other people the password.
| A．What is required | B．What requires |
| C．It is required | D．It requires |
They live on a busy main road. ______ must be very noisy.
| A．There | B．It |
| C．That | D．They |
They are good friends. _______ is no wonder that they know each other so well.
| A．This | B．That |
| C．There | D．It |
Does ________ matter if he can’t finish the job on time?
| A．this | B．that |
| C．he | D．it |
— I don’t know whether I should go abroad or not, Mum.
— I leave _______ to your own judgment whether you should do it.
| A．that | B．it |
| C．this | D．what |
It used to be thought _____ the Earth was flat.
| A．as | B．when |
| C．since | D．that |