given的用法（give）-------more instruction,thestudents would have

填 Given.
这是过去分词做条件状语,相当于 If they had been given.
如果要用had been given的话,要在前面加上主语I,因为它是不能单独使用的.
give）_______more instruction,the students would do the exercise much better.
也是填Given.
再问： 不对吧？难道given提前，既相当于if they were given,又相当于if they had been given吗？依据在哪？
再答： 过去分词做状语，是不分时态的，不但表示过去，将来一样可以。请看：Given one thousand dallors,I'll sell it to you.
再问： 似乎也是，那请问这句话合不合语法？Had been given more instruction, the students would have done the exerciese much better,还是通常人们都不这么说？
再答： 前面不是说了吗？绝对不能这样说。用had been given。。。就一定要把主语写出来。
再问： sorry，刚才想问的是这句话对不对Having been given more instruction, the students would have done the exerciese much better,
再答： 我就知道你想到了这个。也不对。having 。。。。过去分词的完成时态做状语，只能用于真实语气的句子，不能用于虚拟语气。如：Having finished his homework,Tom went home. “俊狼猎英”团队为您解答。
再问： 既然你说过去分词做状语，是不分时态的，那Having finished his homework,Tom went home.是不是可以改为Finished his homework,Tom went home
再答： 不可以。要用主动式Finishing。 “俊狼猎英”团队为您解答。
再问： 我弄个被动出来Having been weakened by successive storms, the bridge was no longer safe，可否为Weakened by successive storms, the bridge was no longer safe
再答： Good.That's right! “俊狼猎英”团队为您解答。
再问： 再举个例子Having been warned by the bandits,he left his valuables at home,也可以为Warned by the bandits,he left his valuables at home？但相应的语法书讲到，从句动作先于主动词时，从句须用完成态的！
再答： 当然，如果从句的动作明星先于主句发生，这种情况最好还是用完成时态。 “俊狼猎英”团队为您解答。
再问： 那我总结一下你的回答看对不对：凡是在虚拟语气中，从句动作一旦提前，只能用一般时态？PS:我提问时那个had been given应该为having been given
再答： That's right. “俊狼猎英”团队为您解答。