助动词have的用法和例句
have作为助动词可以:
1.构成完成时态(have+过去分词): What has happened? 出了什么事? He told me Jane had left. 他告诉我简已经走了。 She will have arrived by this time tomorrow. 明天这时她就会到了。 How long have you been there? 你在那里待了多久?
2.构成完成进行时态(have+been+现在分词) We have been trying to contact you. 我们一直在想和你联系。 She has been teaching there for thirty years. 她在那里任教达三十年。 That was the book he had been looking for. 这是他一直在找的书。
另外,have (got)to还可构成谓语,表示“不得不”: We have(got)to be careful. 我们得小心。 You don’t have to worry. 你不必忧虑。