轨道交通U形梁预制混凝土配合比水胶比控制在（）范围内，砂率为34%～44%。
参考答案：0.38～0.25
The accident happened on such an evening with strong winds________by heavy rain. [ ]
A. appeared
B. happened
C. accompanied
D. mixed
单音词特定码包括（）特定码、（）特定码等。
