2 . I watched as David moved up to the starting line with the other runners. The race started. ________________ that the runway was extremely long for young children, not to mention a child with a heart disease.
我看着大卫和其他赛跑者一起向起跑线上移动。比赛开始了。就在那时，我才意识到跑道对小孩子来说太长了，更不用说一个患有心脏病的孩子了。

3 . Although he was weak, ______ he tried his best to do the work.

A．but

B．so

C．then

D．yet

6 . 首先，我把所有的书籍、报纸和其他的散落在屋子里的东西收集起来放好，然后我扫去所有家具上的灰尘，之后我扫地、拖地。
________, I collected all the books, newspapers and other things scattered in the rooms and put them in place. ________ I wiped the dust off all the furniture. _________ , I swept and mopped the floors.