Some of you may have finished unit one. _____ , you can go on to unit two. 
| A．If you may | B．If you do | C．If not | D．If so |
Both bread and butter ______ on sale in this shop.
| A．is | B．are | C．have | D．has |
The problem is _____ we can master modern science and technology in a short time.
| A．if | B．that | C．what | D．how |
Give it to _____ you think can do the work well.
| A．who | B．whoever | C．whom | D．someone |
Included _____.
| A．all kinds of books | B．was all kinds of books |
| C．were all kinds of books | D．all kinds of books are |
Here _____. This is our classroom.
| A．are we | B．we are | C．you are | D．are you |