A:that
B:thi
C:it
D:one
图示为研究二力平衡条件的实验装置,下列关于这个实验的叙述错误的是( )
下列各项中能正确表示动物与其气体交换部位的有( )
①蚯蚓﹣﹣体壁 ②鲫鱼﹣﹣鳃 ③家鸽﹣﹣肺和气囊
④青蛙﹣﹣鳃和皮肤 ⑤家兔﹣﹣肺.
Nobody could solve this difficult problem alone others' help.
实行依法治国的重要前提是 ()
There are no buses, you'll have to walk.