a fleece of clouds的用法和样例：
- The moon had already come forward with her long face toward the east and a fleece of clouds behind.
- I peep out the porthole and see a sea of clouds.
- I peeped out the porthole and saw a sea of clouds.
- The sun went behind a bank of clouds.
- Behold, I will put a fleece of wool in the floor; and if the dew be on the fleece only, and it be dry upon all the earth beside, then shall I know that thou wilt save Israel by mine hand, as thou hast said.