【单选题】如果一空间力系中各力的作用线分别汇交于两个固定点,则当力系平衡时,可列( )个独立的平衡方程。
【单选题】The number of the people who joined in the journey down the Mekong River _____ four. [ ]
【简答题】( 1 )空间力系中各力的作用线平行于某一固定平面;( 2 )空间力系中各力的作用线分别汇交于两个固定点。试分析这两种力系各有几个平衡方程?
【判断题】空间汇交力系中,各个力的作用线汇交于一点,但不是分布在同一平面内,而是分布在空间。
【单选题】Who joined Cabby in singing?
B.
The Witch and Uncle Andrew
【简答题】(1)空间力系中各力的作用线平行于某一固定平面;(2)空间力系中各力的作用线分别汇交于两个固定点。试分析这两种力系最多各有几个独立的平衡方程。
【单选题】The people who have _____ the club have a chance to ______ the opening ceremony.
C.
taken part in ; attend
D.
attended ; take part in
【简答题】People usually begin___for the celebration a week before the festival.
【单选题】Who is _______ boy playing basketball on the playground. He is Tom. He joined ______ unusual basketball match last year.
【单选题】People usually begin ____ for the celebration a week before the festival.