Common English Grammar mistakes

I have a keen interest in English grammar, grammar of any language for that matter. Following is a list of a few English grammar mistakes that I usually come across, some of which even I make sometimes. I plan to update this list as and when I come across more of these. Feel free to add to the list, especially anything that you spot on this blog :-)

1. Incorrect: he didn't came; did you went?

Correct: he didn't come; did you go?

The tense is carried by the auxiliary verb 'do' -- not by the main verb.

2. When used as an adverb, 'maybe' is a single word meaning 'perhaps'. When used as two separate words, 'may be' is a verb phrase showing possibility. For example, he may be creative or maybe he is just crazy.

3. 'cannot' is a single word. Its shortened form "can't" is also correct. However, writing it as two separate words 'can not' is incorrect.

4. 'up to' should always be two words. There is no word called 'upto'.

5. The adverb sometime (one word) means "at an indefinite or unstated time in the future." For example, visit our place sometime.

The phrase some time (two words) means "a period of time." For example, give me some time to think.

The adverb sometimes (one word) means "occasionally, now and then." For example, sometimes I get confused.

6. The possessive form of a plural word ending in 's' is formed by just appending the apostrophe in the ending 's'. For example, classes' opinions, boys' clothes, etc. The possessive form of a singular word ending in 's' is, however, formed by appending the apostrophe and another 's' in the ending 's'. For example, class's opinion, boss's treat, etc.

7. It's is a contraction for it is or it has. For example, It's a bird, It's been good to know you, etc.

Its is a possessive pronoun meaning, more or less, of it or belonging to it. For example, The bird is known for its ability to fly, It has its own place, etc.