某种零件规格是$\left(20\pm 0.2\right)$mm，下列尺寸的该种零件，不合格的是（   ）

改革开放以来，我国外交事业取得了一个又一个的伟大成就。新世纪的第一年，在上海举行了一次我国迄今规模最大、规格最高的多边外交活动。这个活动是（  ）

某金属R与硝酸银溶液反应的化学方程式为:R + 2AgNO₃₌R(NO₃)₂ + 2Ag,R与硝酸铜溶液不发生反应，关于R的推断正确的是

从方框中选择恰当的句子补全对话。（其中有两个多余）
A: Hi, Mikc!
B: Hello!
A:____ 
B: Yes, but one thing annoyed me.
A: ____ 
B: On the bus, I saw a woman eating bananas and threw the banana skins out to the window.
A: ____ 
B: I told her what she did was not right.
A: You were right. Throwing the litter away will pollute the environment.
B: I Agree with you.
A: ____ 
B: She didn’t take my words at all.
A: No wonder(难怪) you are so angry.