题目

Had Chinese governments andmedical workers not worked harder, COVID-19-related confirmed cases (not, fall) gradually since the mid-February. 答案：【1】would not have fallen一个圆环跑道的内直径为80米，跑道宽5米，要在跑道上铺上塑胶，那么，铺塑胶的部分面积是______平方米．