从生物电的角度而言，细胞膜的去极化意味着兴奋，而超极化意味着抑制。（）
参考答案：对
根据句意用适当的介词填空。
1. I usually download some music ________ the Internet.
2. Mr Li likes to write novels ________ the computer.
3. Bruce doesn't have a computer ________ home.
4. I always do the housework ________ the weekend.
5. Tony sometimes writes ________ his friend.
装球配比对磨矿有何影响？
