1.Unfortunately,women were not admitted to university in the past,____,nowadays,they have got equal rights.A,while B,when C,as D,since2,____ cloning is not allowde in many countries,there are still many people eager for it.A,While B,Since C,Before D,

1.Unfortunately,women were not admitted to university in the past,____,nowadays,they have got equal rights.A,while B,when C,as D,since2,____ cloning is not allowde in many countries,there are still many people eager for it.A,While B,Since C,Before D,
1.Unfortunately,women were not admitted to university in the past,____,nowadays,they have got equal rights.
A,while B,when C,as D,since
2,____ cloning is not allowde in many countries,there are still many people eager for it.
A,While B,Since C,Before D,Unless
3,I felt my heart ____ so fast.
A,beating B,striking C,knocking D,hitting
请问老师答案,最重要的是说明理由.请从语法的角度详细解释,

1.Unfortunately,women were not admitted to university in the past,____,nowadays,they have got equal rights.A,while B,when C,as D,since2,____ cloning is not allowde in many countries,there are still many people eager for it.A,While B,Since C,Before D,
1.A 不幸的是,在过去妇女是不能上大学的.然而,现如今,他们有了（和男性）一样平等的权利.while是转折连词,表示转折及对比.
2.A 虽然克隆技术在许多国家是不被允许使用的,但是还是有很多人渴望使用克隆技术.while是连词,表示虽然,引起让步状语从句.
3.A 该题考查动词辨析.beat表示有节律地跳动.strike指钟表的敲打,或击打.knock是普用语,比如敲门.hit是用力打的意思,具有攻击性.