1.Ma Huan likes to talk to____(人们).
2.He often helps with sports for the English speaking students in the Students' Sports C____ .
3.Let's go to see the old people at the old people's h____
图中由内细胞团到血液组织干细胞、神经组织干细胞以及到各种血细胞、神经细胞的形成是细胞的哪一生理过程?____其实质是什么?____。
先化简,再求值:x2-4x+4x÷(2x-1),其中x=2﹣2.
判断,正确的填“正确”,错误的填“错误”.
两个完全一样的梯形可以拼成一个平行四边形.