如图11-20所示桁架杆件1-2的内力是多少().
A.10kN 拉力
B.15kN 拉力
C.20kN 拉力
D.30kN 拉力
参考答案：C
The boat is ________ small, we can’t put _______ food in it.
A．much too; so many
B．much too; too much
C．too much; much too
D．too much; so much
药典规定赭石以滴定法测定，含铁(Fe)不得少于
A．40.0% B．45.0% C．50.0% D．55.0% E．60.0%
