Jack, my friend, _____ his brother. [ ]
A. are
B. is
C. am
D. be
答案：B
This painting is so valuable that it is rather difficult to calculate _______ its price would be if the museum _______ to sell it.
A．how much; would want
B．what; wanted
C．what; wants
D．how much; wants
根据《GB50009-2001建筑结构荷载规范》规定，《荷载规范》给出了50年一遇的风压采用，但不得小于（）kN/m2。
A.0.5
B.0.2
C.0.3
D.0.6
