问题
单项选择题
环形防喷器关井时，来自液控系统的压力油进入关井下油腔，推动活塞与胶芯迅速向上移动，由于胶芯受（）限制不能上移，在活塞内锥面被迫向井眼中心挤压、紧缩、环抱钻具，封闭井口的的环形空间。
A、顶盖
B、壳体
C、液压压力
D、井内压力
答案
参考答案：A
搜题请搜索小程序“爱下问搜题”
环形防喷器关井时，来自液控系统的压力油进入关井下油腔，推动活塞与胶芯迅速向上移动，由于胶芯受（）限制不能上移，在活塞内锥面被迫向井眼中心挤压、紧缩、环抱钻具，封闭井口的的环形空间。
A、顶盖
B、壳体
C、液压压力
D、井内压力
参考答案：A
| 完形填空。 | ||||
| Jack 1 in the country and he loves 2 in the river near his house, but his father gets a job in a big city and he moves there 3 his family. Their new house has a garden, but the garden is small. Jack 4 very happy. "Is there a river 5 here?" He is asking his mother 6 the first morning. His mother is answering, "No, there isn't, but there is a beautiful park nearby and there is a pool in it. We 7 there this afternoon." Jack is happy now. After lunch, Jack and his mother go to the park. Jack wants 8 near the pool, but there is a sign in front of it. His mother reads it to him. "Warning (注意), this pool is dangerous, 367 people have fallen into it (已掉入)." Jack looks into the pool 9 and he says, "But I can't 10 them." | ||||
|