A. What's the matter?
B. It's red and white.
C. Yes, it is! Thank you.
A: ____
B: I can't find my ball.
A: What colour is your ball?
B: ____
A: Look! Is this your ball?
在生产和科学研究中,稀有气体有广泛的用途。下面情况跟稀有气体的用途无关的是( )
《马说》中写伯乐对千里马起决定作用的句子是:____,____。
已知tanα,tanβ是方程x2+33x+4=0的两根,且α,β∈-π2,π2,则α+β= ( )
数轴上到原点的距离等于4的数是 ____