锅炉或热力系统水、汽取样用的导管,可以采用的材质是()。
A.不锈钢管
B.碳钢钢管
C.黄铜管
D.紫铜管
参考答案:A
—What do you think made Celia so happy?
—________a prize in the recent competition.
A.As she won
B.Won
C.Winning
D.Because of winning
棱长为7分米的小正方体,至少需要( )块才能拼成一个较大的正方体。