Before Vs Ago

any kind of informed opinion, but "ago," to me, simply means something that happened in the past, while "before" implies specifically that it happened before something else - the sentence He came sometime before seems to be missing a word. He came before what? Before she came? Before we did? Before the sun rose?




Generally speaking, you can only replace 'ago' with the word 'before' in reported speech or in a text in which 'before when' is clear. Usually the tense of the verb will be past perfect:

Direct speech: I did it a few hours ago.
Reported speech: He said he had done it a few hours before.

Having gone to bed only three hours before, he didn't hear the alarm when it went off at 5 a.m.
==> Having gone to bed = (Because he) had gone to bed
==> three hours before = three hours before 5 a.m.

May Vs Might

We can use 'may' to ask for permission. However this is rather formal and not used very often in modern spoken English

• May I borrow your pen?
• May we think about it?
• May I go now?

We use 'may' to suggest something is possible

• It may rain later today.
• I may not have time to do it today.
• Pete may come with us

might

We use 'might' to suggest a small possibility of something. Often we read that 'might' suggests a smaller possibility that 'may', there is in fact little difference and 'might is more usual than 'may' in spoken English.

• She might be at home by now but it's not sure at all.
• It might rain this afternoon.
• I might not have time to go to the shops for you.
• I might not go.

For the past, we use 'might have'.

• He might have tried to call while I was out.
• I might have dropped it in the street.

Might is past of may in reported speech. I may go to the park. She said she might go to the park.

http://www.englishgrammarsecrets.com/maymight/menu.php
http://grammar.quickanddirtytips.com/may-might.aspx

Begin Vs Start

Synonyms: begin, commence, start, initiate, inaugurate
These verbs denote coming into being or taking the first step, as in a procedure. Begin, commence, and start are equivalent in meaning, though commence is more formal, and start often stresses the point where inaction turns to action: The play begins at eight o'clock. The festivities commenced with the national anthem. We will stay on the platform until the train starts. Initiate applies to causing the first steps in a process: I initiated a lawsuit against the driver who hit my car. Inaugurate often connotes a formal beginning: “The exhibition inaugurated a new era of cultural relations”

You can start a car or lawnmover, but you can't begin them.
You can begin the movie, but you normally start it.
You start any machine and you also start your bath water.

I would say begin has a higher register than start.

Start usually refers to an activity - The game will start at 4:00. Begin is used for official proceedings - Class will begin on time.

At Vs In

'at' is a point reference: I am at the church, not at the studio. 'In' is a three-dimensional reference: I am in the studio, not out on the street. Often, either will do-- the listener will interpret the situation appropriately.

Fast vs Quick

Quick is a measure of time; fast is a measure of speed. For example: "My car did great at the drag races today. My quarter mile elapse time was a quick 13.99 seconds, and my speed was a fast 102 mph.

Early Vs Soon

early before the due, usual, thought-of or expected time.

soon within a short period of time from now or from some some previously mentioned past time time.

The Rest Vs The Remaining

I think (the rest part) : the part can do it after day or more.
and the ( rem. part) : the part do it in same moment.

Rest is a noun, whereas remaining is an adjective

Some vs Certain

Certain and some define things as either specific or unspecific. But, they can refer to the same number. Certain apples are red. Some apples are red. Pick only the red ones.

"Certain students" adds to the meaning of "some students" the fact that the person making this statement knows which students they are but is not volunteering the names.

definite but not specified or identified; "set aside a certain sum each week"; "to a certain degree"; "certain breeds do not make good pets"; "certain members have not paid their dues"; "a certain popular teacher"; "a certain Mrs. Jones"