口孔~ 不 行 口馬 ？

explain 1：

It's not exactly politeness, but it establishes a distance, which is an aspect of politeness.
It's a little like a subjunctive.
It shows that you do not assume that the other person will help you.
It's like the difference between:

I think you could help

AND

I was thinking you might be able to help

explain 2：

First, all three forms ('I wonder', 'I am wondering', 'I was wondering') are correct and may often be used interchangeably; of course, there are nuances.

Secondly, it's never 'wonder that' (except in rather obsolete English, where it means 'to be astonished' [1]), but rather 'wonder whether/if' (meaning 'to ask oneself', 'to doubt' or 'to deliberate' [2]).

[1] I wonder that you have time to do charity work when you have a full-time job.
(Note that this use does not lend itself to progressive structures with –ing.)
[2] I wonder whether I have time to do this charity work…

Very often, we use 'I was wondering' to phrase a delicate or tentative request [3 & 4]. The past tense is used to indicate reserve or discretion; it does not necessarily express a temporal fact. This structure can also be replaced with the simple present tense [5 & 6].
But the past continuous structure can also be used to show that, at some unspecified past time, we had a question, which has since been resolved [7].

[3] I was wondering if you could give me some advice, Professor.
[4] I was wondering if I could take this book out of the library, please.
[5] I wonder if you could give me some advice, Professor.
[6] I wonder if I could take this book out of the library.
[7] I was wondering whether you needed help, but I see you’re getting along fine.

We use 'I am wondering' to emphasise that one is faced with a decision/choice right now [8 & 9]. 'I wonder' can also be used in these sentences to convey a less immediate aspect [10 & 11].

[8] I'm wondering what to have for lunch: there's nothing in the fridge.
[9] I'm wondering if there's any point in getting this qualification.
[10] I wonder if there's any point in getting this qualification.
[11] I wonder whether he'll come to the party.

resource:http://www.hellouk.org/forum/index.php?showtopic=111395