你认为下列的实验方案中可行的是（）

（Ⅰ）设函数f（x）=|x﹣$\frac{1}{a}$|+|x+a|（a＞0）．证明：f（x）≥2；

（Ⅱ）若实数x，y，z满足x²+4y²+z²=3，求证：|x+2y+z|≤3．

A: Hi, Mary! Did you watch TV last night?

B: ____ What happened?

A: A bus accidentl

B: ____

A: It happened in America!

B: Was it serious (严重的)?

A: ____ Many people died and a lot of people hurt themselves.

B: I' m sorry to hear that. ____?

A: Because the driver wasn't driving carefully.

B: ____?

A: He was talking on his mobile phone at that time.

B: That's new dangerous!

—He's Eddie.

关于物体的内能，下列说法正确的是（　　）