can could 的區別與用法表示請求造句

　　When can I get my test results?

　　我什麼時候可以拿到化驗結果？

　　We can reduce the problem to two main issues.

　　我們可以將這個問題概括成兩個要點。

　　How long can a human being go without sleep?

　　人不睡覺能活多久？

　　The operation could prolong his life by two or three years.

　　這次手術可使他多活兩三年。

　　I could come next week, or the week after.

　　我可能下週來，或者再下一週。

　　You could see from his face that he was lying.

　　從他的表情上你可以看出他在說假話。