021 Check back in a jiffy
解释：东西还没有准备好，等一下回来取。check back，再联系，in a jiffy=quickly，马上，不一会儿。
用法：另有一个用法 I'll be with you in a jiffy，In a jiffy, it will be my birthday。
A: Hi, are my copies done?
B: Not yet. Check back in a jiffy.
A: All right, I'll go get a latte and come back.
B: They'll be done for you.
022 Pick your poison
A: Ooh, these all look good!
B: Pick your poison.
A: Hmm... I'll have the peanut butter cookie.
B: Good! I want the triple chocolate!
023 Those poor children
A: Those poor children. Why do wars mostly affect poor people?
B: I hate wars.
A: We need to tell our leaders "No more war".
B: We have to
024 ~ is pathetic
A: How do you spell "raisin"? With an "i" or an "e"?
B: An "i".
A: What about "streusel"? Two "s"s?
B: No. One. Your spelling is pathetic!
025 What purpose does it serve
解释：what is it used for，他是用做什么的？what is its function
A: Why are you taking vitamin C all day long?
B: These are really good when you're sick.
A: What purpose do they serve?
B: They help strengthen your immune system.
026 I couldn't help it
解释：I couldn't help it.= I couldn't control myself. = I couldn't stop it. 我没有办法；我没办法；我忍不住
A: Why did you laugh in class?
B: I couldn't help it.
A: What was so funny?
B: The way he said "Uranus".
027 to look away
A: Don't look away from me when I'm talking to you.
B: Yes, dad.
A: Did you take the cookies or not?
B: I was hungry!
028 don't push it
解释：在这里it 指运气。别越界哈；不要咄咄逼人；别操之过急。You are pushing it，你过界了，你过分了。
A: Can you make me spaghetti?
B: I'm a little tired, but why not?
A: Thank you. Can you make garlic bread, too?
B: Uh... Okay.
A: And do the dishes?
B: You're pushing it.
029 Are you done yet？
解释：Are you done yet? = Are you finished yet? 你完事了没；你们做完了吗
用法：读快接近 ar yuh....
A: Are you done yet?
A: Hurry up! I'lll wait in the car.
B: Hey, you got any toilet paper out there? Hello? Anyone? HELP!!
030 Knock on wood.
解释：祈求好运，吉人天相， 谢天谢地，asking for luck。
A: You broke your arm again?
B: Yeah. This is my third time.
A: I've never broken my arm. Knock on wood!
B: It's no big deal~