你知道怎么做这个蛋糕吗？

Do you know ___how to make this cake?

你最近怎么样，工作还顺利吗？

___How have you been lately, is work going well?

你平时每天花多少时间锻炼？

___How much time do you usually spend exercising every day?

他向我们展示了如何使用这台机器。

He showed us ___how to operate this machine.