The operation could prolong his life by two or three years.
这次手术可使他多活两三年。
Only with a few people could she be her real self.
只有和几个人在一起时，她才能表现出真实的自我。
I could come next week, or the week after.
我可能下周来，或者再下一周。
Could you put me through to the manager, please?
请帮我找经理接一下电话好吗？
Could you just help me with this box, please?
请帮我搬一搬这箱子好吗？