制作人字拔杆时,要求两根桅杆相交角度不宜太大和太小,一般为65°左右。角度太小,人字拔杆就不稳定;角度太大,桅杆的受力就大,从而会降低起重的能力。
参考答案:对
—What did Mr Zhou say?
—He invited me the party and told me late.[ ]
A. for; to be
B. for; not to be
C. to; not to be
D. to; to not be
“气之主”是指
A.心B.肺C.脾D.肝E.肾