螺旋和盘山公路都是____的变形。

如图，给出下列条件：其中，能判断AB∥CD的是 （    ）

 ①∠1=∠2          ②∠3=∠4      ③∠B=∠DCE      ④∠B=∠D．

单词拼写
(1)I called you last night but you didn't answer me. What was h____ .
(2)I looked for my cat e____ , but I didn't find it.
(3)He is good at math, but he failed the exam this time. I can not i____  how strange it is.
(4)Both Tom and Tim have t____ to the ball game. They’ll go and watch it.
(5)Liu Yang becomes a national h____  because she is the first Chinese woman that has been to the space.
(6)Lily m____  her English teacher while she was shopping in the mall.
(7)There are still lots of p____  families in China. We should help them.
(8)This problem is too s____ . Even a kid can work it out.
(9)I had a car accident yesterday. L____ , there was nothing wrong with me.
(10)Do you make the bed for your parents?  No, they make the bed by t____ .

以水为溶剂进行中和滴定的原理是：H₃O⁺+OH^-＝2H₂O．已知液态SO₂和纯水的导电性相近，因为液态SO₂也会发生自离解：SO₂（l）+SO₂（l）SO₃^2-+SO²⁺．若以液态SO₂为溶剂，用SOCl₂滴定Cs₂SO₃，则以下叙述错误的是                     （   ）

We need to come up with a/an________and make a decision at once.