依据图示回答：图A～C是分子的微观示意图，其中“ ”表示氢原子，“○”表示氧原子．

①表示化合物的是图____．

②可表示A转变为B的化学方程式是____，它属于基本反应类型中的____ 反应．

一节干电池的电动势为1.5V，蓄电池的电动势为2V，下述说法正确的是（   ）

放在水平桌面上的茶杯，对桌面有压力，下列说法正确的是(   )

完形填空。
   A man was walking along the street when he saw a woman struggle（奋力）with a large box. It was half in and half 1 of her car. He was a helpful kind of man, so he went up to the woman and said, “Let me give you a hand with that box. It looks very 2.”
“That’s very kind of you,” the woman said. “I’m having a lot of 3with it. I think it’s struck（卡住）.”“Together we’ll soon move it,” the man said. He 4 into the back seat of the car and took hold of the other end of the box. He said, “I’m ready.” And he began to5 hard.
   For several minutes the man and the woman struggled with the box. Soon they were 6 in the fact. “Let’s rest for a minute,” the man said. “I’m sorry, but it 7 stuck.” A few minutes later, the man said, “Let’s try again. Are you ready?” 8 of them took hold of the box again. “One, two, three!” the man said, and they went on with their struggle.
   At last, when they were very tired, the man said, “You are9. It really is stuck. I don’t think there’s 10 we can get it out of the car.”“Get it out of the car!” The woman cried. “I’m trying to get it in!”