1．A formal contract was signed between the two companies.
2．Some of the studies show positive results, whereas others do not.
3．Safety regulations are being ignored by company managers in the drive to increase profits.
4．She underwent (经受) an operation on a tumour in her left lung last year.
5．If we had taken such effective (有效的) measures much earlier, the river would not be polluted so seriously now.
6．He was completely ignorant (无知的) about the country's political system.
Ⅱ.单句语法填空
1．This time she's leaving for good; you can't expect to see her.
2．I hope the weather will clear up before Sunday.
3．All their attention was focused on only one thing — how to solve the problem of water pollution.
4．When I was little, my mother used to sit by my bed, telling (tell) me stories till I fell asleep.
5．The robot equipped (equip) with a camera can do many things for mankind.
6．First of all, you have to wash your hands.
7．The festival will be great for our city and for the country as a whole.
8．You will benefit from jogging a lot if you stick to it.
