烟尘通常是指飘浮于空气中直径多少的颗粒（）
A.小于0.1微米
B.大于0.1微米
C.大于0.1毫米
D.小于0.1毫米
参考答案：A
离合词
In such freezing weather,water pipes are easy to and water will escape from the . [ ]
A. break;break
B. crack;burst
C. burst;crack
D. break;burst
