If you mean "It is possible that you will be able to attend," use Possibly, you may attend. The word possibly is not necessary: its doubtful meaning is included in the form "may attend." Therefore, we make it absolute, separated from the grammar of the sentence by the comma.
"So few" is correct for things that may be counted.
It is Can you please stop
The issue is not grammar, but pronunciation. In words beginning with h but not stressed on the first syllable the h may be silent.
No.I'm assuming you're asking if that's the correct grammar, and it's not. The correct phrase would be "May I please go?".
Use on. Agenda means (a list of ) things to do.
Yes
"So few" is correct for things that may be counted.
For more than 20 years of existence this may be my first time to visit here is not correct grammar.
It is Can you please stop
Both are correct and may have different meaning, according to context.
Although "in a train" may seem correct, the more commonly used phrase is "on a train".
May I is the correct form for seeking permission.
As the subject of a verb, yes. Otherwise use Joe and me. We say "Joe or I will answer your questions: you may ask Joe or me."
He was born in Essex. You may want to improve your grammar. As "were" is not correct. Where would be correct as it involves a place.
No. With things that may be counted we use "fewer."
The issue is not grammar, but pronunciation. In words beginning with h but not stressed on the first syllable the h may be silent.
No.I'm assuming you're asking if that's the correct grammar, and it's not. The correct phrase would be "May I please go?".