问题
多项选择题
分馏系统冲洗油的作用是（）。
A、冲洗置换管线
B、补充液位
C、降低温度
D、为泵提供封油
答案
参考答案：A, B, D
搜题请搜索小程序“爱下问搜题”
分馏系统冲洗油的作用是（）。
A、冲洗置换管线
B、补充液位
C、降低温度
D、为泵提供封油
参考答案：A, B, D
| Reading comprehension. (阅读短文，选择最佳答案) |
| Everybody needs water. All plants need water. We use water to wash cups, cars, clothes and ourselves. Where does all water come from? It comes from the clouds. The clouds can change into rain. Some of the rain goes down the ground. Some of the rain water goes down the mountains into streams (小溪). The streams come together to make rivers and lakes. Water can change itself. When water gets very cold, it becomes ice. When water gets very hot, it becomes steam (小蒸气). |
| 1. _____ need water. |
[ ] |
A. Only animals |
| 2. We usually clean our clothes with ______. |
[ ] |
| A. steam B. clouds C. water D. rain |
| 3. The water in the streams comes from the _____. |
[ ] |
| A. river B. lake C. wind D. clouds |
| 4. When the weather gets very , water changes into ice. |
[ ] |
| A. warm B. hot C. cool D. cold |
| 5. Where does steam come from? |
[ ] |
| A. it comes from the clouds. B. it comes from plants. C. it comes from very hot water. D. it comes from very cold water. |