Question

【题目】After the training, Bruce and Ian could operate the machines by ________. (them)

Answer 1

【答案】themselves

【解析】

句意：训练结束后，布鲁斯和伊恩可以独自操作机器。

根据固定搭配by oneself“独自”可知，介词by后接反身代词。故填themselves。