他们对此现象进行了讨论，认为这是由于冰的熔化和凝固引起的．关于冰熔化的原因．他们提出了以下三种猜想：

猜想l：冰块的厚度小．

猜想2：金属丝的温度低．

猜想3：金属丝对冰块的压强大．

如图所示，abcd是一矩形的四个顶点，且ab=cd=20cm，ad=bc=40cm，电场线与矩形所在平面平行，已知a点电势为7V，b点电势为13V，则（     ）

根据下列句子所给的汉语注释，写出单词的正确形式，使句子意思完整。每空只填一词。

1. Can you find Hepu on the ____ (地图) of Guangxi?

2.–-What does your aunt look like?

  ---She's of medium build, and she has long____ (头发).

3.---Which of the two T-shirts do you like better?

  ---The____ (黄色的) one.

4. My uncle goes fishing to relax every____ (星期天).

5. She began to learn to ____ (做饭) when she was eight years old.

6. When I'm down or tired, I ____ (更喜欢) movies that can cheer me up.

7. The geography teacher tells us that the Caspian Sea is 1,025 meters ____ (深的).

8. The boy who is often absent from classes will ____ (不及格) his exams this time.

9. Hangzhou is____ (广泛地) known for the West Lake and Longjing Tea.

10. There are over ____ (三十) new words in Unit 3 and I've already memorized all of them.