he must have studied English for many 为什么要用have而不是has

He spoke English well.He( ) studied the language for years括号处为什么填must have he must have studied English for many 为什么要用have而不是has He must have studied English last night,___he?A.don'tB.haven'tC.hasn'tD.didn't You have failed in the test again .You ( ) hard at your subject .A should have studied B must have studied C may have studied D need have studied 反义疑问句:you must have studied English for three years,_____?he can't speak English well,____?it must be going to rain tomorrow,______?he must be there now,______?what colors,______? He must have learn English for three years,___?A.hasn't he B.haven't he C.mustn't he D.didn't he网上有这种说法：陈述部分有must 的疑问句,疑问部分根据实际情况而定.He must be a doctor,isn't he?You must have studied English f 在He is said to have studied ehglish . 关于He can't be at home,isn't he?此句是否为反义疑问句?请问和He isn't at home,isn't he?有什么关系?为什么?也请解释一下“can't”在此处的意思.He must be a doctor,isn't he?You must have studied English for three years, You must have studied English for many years是现在完成时吗原因 阅读表达If you have studied a foreign language,you must know how difficult 翻译：Lingling must have studied French before,for she can speak it fluently. I told Sally how to get there,but maybe I ()for here.a.must have studied b.might studyc.should have studied d.would study we ()last night ,but we went to the concert insteada.must have studied b.might studyc.should have studied d.would study He must have done nothing but ____ should have studied Rober is said_____abord, but I do not know which cuntry he studied inAto have studied B to have studing C to have been studing He looks tired,he _______ too little sleep.A must have had B must have C must have been is it he must have fallen or he must have fell?whythank you