4)The question is whether we can finish our work by tomorrow evening.

　　问题在于我们能不能在明晚以前完成这项工作。

　　(英语主从复合句——汉语简单句)

　　5)While we were operating the machine tools, we were very careful.

　　我们在操纵机床时非常小心。

　　(英语主从复合句——汉语简单句)

　　6)There are some metals which possess the power to conduct electricity and ability to be magnetized.

　　某些金属具有导电的能力和被磁化的能力。

　　(英语主从复合句——汉语简单句)