6 合同期限
3句英文任你选
How long shall we make the contract for?
合同期订多长时间?
Initially, it would run for one year，a kind of trial period.
开始先订一年当作试验期吧。
This contract is valid for four years.
这份合同三年有效。

半个句型要记牢
contract period (合同期限)

Tip:
询问合同期限用how long，合同期满是 contract expiry，valid意思是, "有效的"，反义词是 invalid。