在巷道支梁上起吊时,必须先()。
A.固定支护
B.加固支护
C.固定
D.支护
参考答案:B
The government is ___ everyone to save water.
A.appealing
B.appealed for
C.appealing of
D.appealing to
计算题:某锅炉水冷壁上下联箱间的水冷壁管长39.6m,上联箱和吊杆固定,当温升为300℃时,下联箱下移多少毫米?(线膨胀系数为αt=12×10-6m/m℃)