【单选题】In America, ______ is compulsory and free.
A.
the higher education and elementary education
B.
the elementary education and vocational education
C.
the secondary education and higher education
D.
the elementary education and secondary education
【简答题】The training course is elementary.
【简答题】A.basic B.young C.small D.elementary
【单选题】下列四种产品中应当计入当年国内生产总值的是
【判断题】在铰链四杆机构中,当行程速比系数 K > 1 时,机构一定有急回特性。
【判断题】在铰链四杆机构中,当行程速比系数K>1时,机构一定有急回特性。
【判断题】( ) 当行程速比系数 时,机构一定有急回特性。
【判断题】四杆机构中,当行程速比系数K>0时一定有急回特性。A. 对 B. 错 C. 多余选项 D. 多余选项,直接忽略