已知函数 f (x)=|2 x-a| +a

(Ⅰ)当 a=2 时，求不等式 f (x)≤6 的解集;

(Ⅱ)设函数 g(x)=|2 x-1| ，当 x∈R时，f (x)+g(x)≥3，求 a 的取值范围。

设函数f(x)，则使得fx2成立的x的取值范围是___

Jack is a teacher of English. He is not young，but he is not old. He has a round face and black hair.He is tall. There are fifty students in his class. They all like him.Now it's in the afternoon. Look，some students are working in the classroom. Jack is there，too.He is helping them to study English. He is a good teacher， and he is a good friend of them all.

()1. What does Jack do?

A. He is a worker.

B. He is a teacher.

C. He is a doctor.

D. He's a nurse.

()2. What colour is his hair?

A. It's black.

B. His heir is white.

C. It is brown.

D. He has yellow hair.

()3. How many students are there in his class?

A. There are fifteen students in his class.

B. There's fifty.

C. He has fifty.

D. There're fifty in it.

()4. Jack is a good teacher，isn't he?

A. Yes ，he isn't.

B. No ，he is.

C. Yes，he's.

D. Yes ，he is.

()5. What are the students doing in the classroom?

A. They are walking there.

B. They are doing their lessons.

C. They are helping their teacher.

子由使契丹.苏轼

云海相望寄此身，那因远适更沾巾。

不辞驿骑凌风雪，要使天骄识凤麟。

沙漠回看清禁月①，湖山应梦武林春②。

单于若问君家世，莫道中朝第一人③。

[注]①清禁：皇宫。苏辙时任翰林学士，常出入宫禁。②武林：杭州的别称。苏轼时知杭州。③唐代李揆被皇帝誉为“门地、人物、文学皆当世第一”。后来入吐蕃会盟，酋长问他：“闻唐有第一人李揆，公是否？”李揆怕被扣留，骗他说：“彼李揆，安肯来邪？

本诗尾联用了唐代李揆的典故，以下对此进行的赏析不正确的两项是( )

所有偶数都是2的倍数，也都是合数。()