有一铝块,下列做法会使其质量发生变化的是[ ]
A.把铝块加热到100 ℃
B.把铝块压制成一张铝箔
C.用锉刀将铝块表面打磨平滑
D.把铝块从赤道带到南极
答案:C
如图,济南某地点两分两至日时正午射入窗户的太阳光线,其中代表冬至的是
A、1
B、2
C、3
D、没有
连词成句。
1. does, sing, he, well
__________________________________?
2. how, students, many, there, are
3. bring, food, water, and, you, with
__________________________________.
4. kind, of, this, paper, feels, soft, very
5. a, watch, few, students, every. it, day, only