在图中,A、B两球相互间一定有弹力作用的图是( )
①有芒×有芒→有芒 ②有芒×有芒→有芒215+无芒70
③有芒×无芒→有芒 ④有芒×无芒→有芒101+无芒97.
按要求变化下列各句(1)Lisa was on duty yesterday afternoon. (对划线部分提问)____ was on duty yesterday afternoon?(2) The students had a piano lesson last Monday. (改为否定句)The students ____ a piano lesson last Monday.(3) Claudia was at the culture club this morning. (改为一般疑问句)____ at the culture club this morning?(4) It’s Friday today. (对划线部分提问)____ is it today?(5)They were at the office yesterday. (对划线部分提问)____ they yesterday?