In our daily life, direct questions are usually used to ask for information we do not know. Direct questions are either yes/no questions such as "Are you married?" or information questions such as "Where do you live?".
It's OK to ask your friends or someone you know well direct questions. But they can seemabruptand impolite at times, especially when you are asking a stranger. For example, if you come up to someone and ask "What time is it?" or "Can you move?", he/she may refuse to help you. It is certainly correct to ask questions in this way, but it's very common to make these kinds of questions more polite by adding "Excuse me" or "Pardon me" to begin your questions. "Excuse me, when does the bus leave?" or "Pardon me, may I sit here?" sounds more polite.
It's also possible to use "can" in more informal (非正式的) situations. In the past, "can" was not used when asking for something, but only to refer to abilities. In the United Kingdom, Cambridge University publishes (出版) English teaching materials with the phrase "Can you lend me" "Can I have", etc. In the United States, this form is still considered to be incorrect, especially for written English, and "May I have" is preferred. Questions with "can" are made more polite by using "could": "Pardon me, could you help me?"
"Would" can also be used to make questions more polite. "Would you let me borrow your pencil?" is also polite.
Another way of making direct questions more polite is to add "please" at the end of the questions. We can say "Could you help me, please?" "Please" should not appear at the beginning of the questions.
