我建议签一份为期四年的合同。
还能这样说：
I advise to sign a four-year contract.
I suggest that the contract should be signed for four years.
谚语：
A man without money is no man at all.
一分钱难倒英雄汉。
10. You shouldn't make a contract until you have studied its provisions carefully.
你应该先仔细研究合同的条款，然后再签订。
还能这样说：
You can sign the contract once you make a research into the items carefully.
You must make a close study on the provisions prior to signing the contract.
应用解析：
make provision for 为……做好准备，为……预先采取措施;
run out of provisions 缺少粮食(或其他供应品)
11. We are fully satisfied with the terms of this contract.
我们非常满意这份合同的条款。
还能这样说：
We are pleased with the provisions in the contract.
The provisions in the contract satisfy us pleasantly.
应用解析：
in terms of 从……方面，从……角度来讲;换算，折合;
in the long term 从长远观点来看
12. We'd like to make the contract to be valid for two years.
我们把合约的期限定为两年。
还能这样说：
We would like to sign a two-year contract.
We want the contract to be firmed for two years.