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!”
）与丙烯的共聚物是一种高分子阻燃剂，具有低毒、热稳定性好等优点．完成下列填空：