1.为何用has而不用had:Can you make sure where Lucy has1.为何用has而不用had:Can you make sure where Lucy has put the dictionary?2.have taken和having taken,为何是haveLily have taken my umbrella by mistake.

1.为何用has而不用had:Can you make sure where Lucy has1.为何用has而不用had:Can you make sure where Lucy has put the dictionary?2.have taken和having taken,为何是haveLily have taken my umbrella by mistake. he was one of the greatest writers that had ever lived.此处为何用that而不用who引导 We were surprised at the news____john had won the match.空格处为何用that而不用which 制备Mg为何用MgCl,而不用MgO,制备Al为何用Al2O3,而不用AlCl3? 制备Mg为何用MgCl,而不用MgO,制备Al为何用Al2O3,而不用AlCl3? don,t exercise on an empty stomach because it can cause headaches为何用on而不用with 测氧气分数时为何用红磷而不用白磷? 钱币为何用铜制造而不用铁 炼钢为何用纯氧而不用空气? The man has two sons ,both of___are doctors空格中为何用Which,而不用them.讲得好加悬赏金 Can I have _____,Mum?A apple B some apples C any apples疑问句中为何用some而不用any I agree,but the problem is__he has refused to.为何用that 不用what 句子解析,he has experienced the ups and downs of life这里为什么用has而不用had? 如图：1、第一处为何用“the”?2、第2处为何用动词“took”而不用其他动词? Can you make sure ___where Alice has put___ the gold ring?为什么填where Alice has put?为什么用has?不用had? He is amazingly cheerful,considering all he's had to go through.为什么用has had to go 而不用has gone呢？ it had some pages missing.为何用missing 而不能用miss? How can you possibly miss the news It ________on TV all day long.为什么用has been 不用had been