《论语》中教育弟子专心求学的几句话是:____,居无求安,敏于事而慎于言,____,可谓好学也已。
受精作用是在哪完成的 ( )
下列实验操作错误的是( )
John as well as the other children who ______ no parents ______ good care of in the center.