Some of the students have already learned enough English to _______a conversation with an English speaker. A.go on (vi.) B.carry on (vt. Vi.) C.keep on D.hold on 答案:B 解析: go on (vi.) carry on (vt. Vi.) 而keep on和hold on不合题意。一本初中物理书平放在水平桌面上,如何测定它对桌面的压强?请你写出你选择的器材,实验步骤及压强表达式.
器材
步骤