动词填空 可适当填加助动词或情态动词。

      Last Sunday, my friends Wang Tao, Zhang Jun asked me to go    1     (swim) with them. Soon we got

to the river. They were swimming in it. But I couldn't swim. So I    2    (sit) under a big tree and watching

a little boy    3    (play) with a ball near the river. But the ball    4    (fall) into the water and he fell into the

water, too.

      I was standing up and    5    (call) for help. But my friends    6    (be) far from me and they    7    (not

hear). So I jumped into the water. I didn't know how to swim in it, but I    8    (take) the little boy out of the

water. His parents thanked me very much. They said, "You are a good boy, a good young pioneer."

     When my friends knew this, they all smiled and    9    (say), "You    10    (swim) now."

1._____ 2._____ 3._____ 4._____ 5._____

6._____ 7._____ 8._____ 9._____ 10._____

将纯铜片和纯锌片按图示方式插入同浓度的稀硫酸中一段时间，以下叙述正确的是

A．两烧杯中铜片表面均无气泡产生

B．甲中铜片是正极，电极反应：2H⁺+2e→H₂↑；乙中锌片是负极, 电极反应：Zn-2e→Zn²⁺

C．两烧杯中的pH值均增大

D．产生的气泡速率甲比乙慢