大家好，请问一下
http://www.macmillandictionary.com/dictionary/british/if_1
看到这样的句子：
If anyone has found a bunch of keys, would they please leave them on my desk.
If you should happen to meet Diane, would you give her a message.
这两句从语气上来看有疑问的意思：
如果....，可以请他们/请你....吗？
而且would摆主词前面，
但后面的标点却是句号而非问号，该如何理解呢？不能改用问号吗？
谢谢。