‘some time’ ‘sometime’ or ‘sometimes’?

Some time (with two stresses) means quite a long time.

Example:

She has lived in China for quite some time, so she speaks Mandarin quite well.

Sometime refers to an indefinite time, usually in the future; it means one day.

Example:

Why don’t we meet for a drink after work sometime next week?

Sometimes is an adverb of frequency, meaning on some occasions or more than once.

Example:

Sometimes, in quiet leisurely afternoons, the children lay in the shade of the guava tree in the garden, reading.