quite / quiet

quite: adverb of degree meaning 'very' or 'rather'

Examples:

This test is quite difficult.
He was quite exhausted after the long journey.

quiet: adjective meaning the opposite of loud or noisy

Examples:

Could you please be quiet?!
She's a very quiet girl.

sensible / sensitive

sensible: adjective meaning 'having common sense' i.e. 'not stupid'

Examples:

I wish you would be more sensible about things.
I'm afraid you aren't being very sensible.

sensitive: adjective meaning 'to feel very deeply' or 'to hurt easily'

Examples:

You should be careful with David. He's very sensitive.
Mary is a very sensitive woman.

shade / shadow

shade: protection from the sun, a dark area outside on a sunny day.

Examples:

You should sit in the shade for a while.
It's too hot. I'm going to find some shade.

shadow: the dark area created by something else on a sunny day.

Examples:

That tree casts a large shadow.
Have you every noticed your shadow getting longer as it gets later in the day?

some time / sometimes

some time: refers to an indefinite time in the future

Examples:

Let's meet for coffee some time.
I don't know when I'll do it - but I will do it some time.

sometimes: adverb of frequency meaning 'occasionally'

Examples:

He sometimes works late.
Sometimes, I like eating Chinese food.