Look! There is a whole crowd of people over there．Go and see what __________ and if it is a bargain，buy it．
| A．is selling | B．has been selling |
| C．is being sold | D．has been sold |
Please do me a favor —_____ my friend Mr. Smith to Youth Theater at 7:30 tonight.
| A．to invite | B．inviting | C．invite | D．invited |
36. You and I could hardly work together, _____? 
| A．could you | B．couldn’t I | C．couldn’t we | D．could we |
Do you consider it any good _____ psychology?
| A．to learn | B．to have learned | C．learning | D．having learned |
Lack of money led the company to a situation _____ they had to decide whether they should keep on with their production.
| A．when | B．where | C．that | D．which |
. _____ by the advances in technology, many farmers have set up wind farms on their land.
| A．Being encouraged | B．Encouraging |
| C．Encouraged | D．Having encouraged |