一个人不受欢迎，可能有多方面的原因，而受欢迎的人都具有以下共同的特征（   ）

将一副三角板如图放置，使点A在DE上，∠B=45°, ∠E=30°，BC∥DE则∠AFC的度数为（   ）

多细胞生物体经过细胞的分化形成了不同的（   ）

A Party

Donny: Kim and I want to throw a goodbye party for Chuck.

It's this Saturday night at Kim's house.

Tina: That's a good idea. What do we need to do?

Kim: We need to buy some food and drinks. Tina, please meet me at 10 o'clock on Saturday morning. We'll go shopping.

Tina: OK!

Donny: Pam, you have a lot of great CDs. Please bring your CDs.

Pam: Sure! I will take care of the music.

Tina: Did you invite Chuck's other friends?

Donny: Yes. We already invited them and gave them Kim's address. It will be fun.

Tina: Wow! I can't wait for the party.

Chuck: Hey! What party?

基因工程中，限制性核酸内切酶只在获得目的基因时使用。