The reason why he succeeded is ______ he worked very hard.
| A．why | B．that | C．whether | D．how |
A mistake ______ have been made on our bill. We didn’t order any fish today.
| A．should | B．would | C．could | D．must |
As you wander through the streets, you see thousands of masks but you have no idea_____ the faces behind them look like.
| A． which | B．what | C． that | D．how |
_______ to carry out the plan in time, they will make careful preparations.
| A．Determine | B．Determined |
| C．Having been determined | D．Being determined |
I never thought of it before, _______ all that my parents had done for me for granted.
| A．taken | B．to take | C．taking | D．Took |
______ number of people, who have access to private cars, is on____ increase in recent years.
| A． A ; the | B． A; an | C．The ; the | D．The ; / |