some times一定要用完成时态吗不是完成时态,用可延续性动词行吗

some times一定要用完成时态吗不是完成时态,用可延续性动词行吗 有already一定要用完成时态吗? not until一定要用完成时态么 有for many years 用什么时态?一定要用完成进行时吗？只是完成时不对吗？ sometimes,some times,sometime,sometime time用于什么时态? 很简单的两个汉译英!我不吃饭 I don't eat我没有吃饭 I have not eaten.这两个翻译对不对,是不是“没有”的翻译,一定要用完成时态? 哪些时间状语用完成时态 some times he left his family some times为什么错呢为什么不能用some times 可以说some times 为什么新概念上说没有这个用法 应该用several times 而不能用some times? Our headmaster middle school students not to smoke for several times.为什么不能用过去式而用完成时?Our headmaster （ ） middle school students not to smoke for several times.为什么不能用told 而用has told? sometime,sometimes,some time,some times的异同?以及它们的用法?它们对应使用哪种时态? i ___the book twice when i was in the bookstore.A.have read B.was reading C.had read D.read答案是D.可是有twice不应该用完成时态吗.帮忙解答一下吧.多谢. For so many years 后面要用完成时态么?还是什么时态都可以? 有关hear of的用法hear of可以用完成时态吗?后面可不可以跟宾语从句? yet什么情况下用一般时态,什么情况下用完成时态,如何区分When and where to build the new factory ____yeta,is not decided b has not decided为什么选B不选A 完成时态 be supposed toNancy is supposed to have finished the chemical experiment at least two weeks ago. 为什么句中要用完成时态,而不直接用be supposed to do? many times 用于什么时态