混凝土在运输过程中可以向拌合物中加水。

阅读理解。

     It was Christmas, and there was a big party in the house. Guests came and went, but the

party went on. They were drinking happily. Then the bell rang. Several people shouted, "Come

in!"A small man opened the front door and came in. Nobody knew him but the host went to meet

hirn and took him to have a drink. The man sat there happily for an hour and a half and drank. Then

suddenly he stopped and looked at the host."Do you know me?"he said."Nobody asked me to this

party.I don't know you.I don't know yrour wife and I don't know any of your guests. My wife and

I wanted to go out in our car, but one of your guests' cars was in front of our gate, so I came here to

find him and my wife is waiting in our car for me to come back."

根据短文内容每空填一个英语单词。

     It was Christmas Day. There was a 1.____  in the room. When the bell rang, the guests were

2.____ 3.____. A short man 4.____in. The host 5.____ him  to 6.____a 7.____.The short man

knew 8.____ of the people.  He came to the house to 9.____a man. The man's car was in front of

his car. The short man's wife was  10____  in their car; perhaps she got very angry.

(1)写出一个以离子浓度表示的电荷守恒等式：                       。

(2)写出一个含有c(OH^－)和c(H^＋)的等式：                           。

(3)根据Na₃PO₄中Na、P原子个数关系，写出一个含有c(Na^＋)和c(PO)的等式：                           。

Danny and Jenny are ____________ with the skipping rope.[ ]

A. skip

B. skipping

C. skipped

下面句子中，加粗词语使用正确的一项是[ ]

A．这座寺庙经过数月的修缮，如今已整修完毕。整座庙宇看上去古朴庄严，惟妙惟肖。

B．冬去春来，夏隐秋至，一年四季，周而复始，变化无常。

C．每逢节假日，中央大街两旁的店铺，就会顾客盈门，生意葱茏。

D．家中的相册里，总有一些年代久远、发黄褪色的老照片。这些照片的背后，往往隐藏着一些鲜为人知的故事。

当数据库的存储结构改变时，可相应修改______，从而保持模式不变。