首先根据句意及首字母提示完成句子。

P ____ their train has been delayed.

解答:这道题的答案是perhaps.

请就这个题详细讲解一下几个表示“可能的”（probable/possible/perhaps/likely/maybe）词用法及区别。

解答：Possible:强调客观上有可能性,但也常常暗示”实际上希望很小”,常用的句式为

“It is possible for sb to do sth.”或”It is possible +that 从句”。作表语时不能用人作主语。

Probable:主要用来指有根据、合情理、值得相信的事，带有“大概，很可能”的意味，语气较Possible强。

常用的句式为“It is probable+从句”。

作表语时不用人或不定式作主语。

Likely:侧重从表面看，某事很可能发生，与Probable意思相近。既可用人也可用物作主语。

常用的句式为：“Ït is likely that从句 ”或”sb. is likely to do sth”

注意:不能说:It is likely for sb to do sth.

典题：Look, dark clouds are gathering. It is ___to rain soon.,

A. probably B.possibly C.likely D.perhaps

点拨：不能说It is perhaps to …;A, B都是副词，所以不能选择 A或B。常不用 It is probable to do sth.但可以说It is possible that从句.请看以下例句：

It is possible for him to finish work.

It is possible that he shall finish work.

It is probable that he shall finish work.

It is likely that he will come.

He is likely to come.

至于probably;perhaps

这两个副词都有“可能”的意思，用法/区别如下：

probably“很有可能；十之八九”，其语义较强，可能性较大。在否定句中，probably不能紧跟在否定词之后。例如：

It will probably be fine tomorrow．明天大概会是晴天。

译：她大概不会来这里。

正：Probably she won’t come here．

正：She probably won’t come here．

正：She won’t come here probably．

误：She won’t probably come here．

perhaps是副词，意思是“也许、可能”，在句中作状语，相当于maybe，常位于句首。

Perhaps she’ll come this afternoon. 她可能今天下午来。

Perhaps you put the letter in your pockets. 大概你把信放在衣袋里了

所以，根据以上解释，这一道题如果没有其他语境限制的话，前面那个以p开头的单词既可以是perhaps也可以是probably.只是可能性大小不同而已。