摘要： could have done: 本可以做但是实际没有 could还能表示能力 但是should不能表示能力 You could have done better.// 实际做的不是很好 The accident could have been prevented. // 本来可以被阻止的 // c 阅读全文

摘要： must 推测: 肯定是，但不一定是 The tall fellow must be a basketball player. // she can't be a basketball player. You must think i'm stupid. He must be playing bas 阅读全文