面值20元和50元人民币上（图中）景观所在地区主要的少数民族分别是（  ）

    My name is Peter.I'm 11 years old.  I'm 1.40 metres. I like winter very much, because I can make a snowman and play in the snow. It's very interesting. My friend, Mike, is l year younger than me, but he is 5 cmtaller than me. He likes winter, too, because he likes ice-skating. Next winter holiday, we're going to Harbin to see the snow in north of China. It would be very cold, and we can play with snow every day!

玻璃店裁切玻璃时都用金刚石刀，这是因为金刚石的____ 大；用塑料皮包裹在老虎钳的手柄上，是利用了塑料的____ 差这一特性；选用钨做灯丝的原因是钨的____ 高。