无烟煤其可燃基挥发分含量小于()的煤。
A.10%
B.15%
C.20%
参考答案:A
We prefer to measure our football team’s success the number of fans attending rather than the number of games won.
A.in need of
B.in terms of
C.in favor of
D.in honor of
自然组织谐波的作用是()。
A.增加可视帧频
B.增加界面分辨力及清晰度
C.增加高频超声的穿透深度
D.提高声输出功率
E.减少超声的衰减