A:夏天我们家乡昼长夜短
B:黑龙江的小麦在春天播种
C:台风常在浙江沿海登陆
D:电子产品的更新换代
这本书是一部( )
先化简:再求值:(1﹣1a-1)÷a2-4a+4a2-a,其中a=2+2.
—You'd better take good care of her so that she can get well very soon.