缫丝时有一道工序是将蚕茧用热水浸泡后缫丝，在蚕茧内死亡的是家蚕的（   ）

当水星运行至地球和太阳之间，如果三者能够连成直线，便会产生水星凌日现象．如图能反映水星凌日，水星、地球和太阳三者位置关系的示意图是（　　）

      There are  1 days  2 a week. They are  3 , Tuesday, Wednesday, Thursday, Friday, Saturday and4  .Sunday is the first day 5 a week. Monday is the second day of a week. The last day of a week is Saturday.  6  China, people work 7days a week. They go to work from Monday 8  Friday. They don't go to work 9 Saturdays and Sundays . They stay 10  home.

人体的内环境是指（ ）