The following words are easily confused and misused:
Abjure: swear or promise to give up; perjure: swear falsely under oath.
e.g. There were times when Christians were forced to abjure their faith.
e.g. If you perjure in a court of law, you will be prosecuted.
Some time: a period of time; sometime: approximately (as an adverb), former or occasional (as an adjective); sometimes now and then (as an adverb).
e.g. We have been for the train for some time.
e.g. Why don't you visit me sometime?
e.g. She was my sometime girlfriend.
e.g. Sometimes I like her, but sometimes I don’t.
Lay: put down (a transitive verb requiring an object); lie: be in a resting or horizontal position (an intransitive verb, without an object).
e.g. To lay down one's life to save the life of another is a courageous act.
e.g. They laid a cable under the river bed (past tense).
e.g. They had laid a cable under the river bed (past participle)
e.g. I want to lie on the sofa (present tense).
e.g. I am lying on the sofa (present participle).
e.g. I lay on the sofa (past tense).
e.g. I had lain on the sofa for an hour (past participle).