Write questions with how long and when.
EXAMPLE:
Bob and Alice are married. How long —?
ANSWER:
have they been married
EXAMPLE:
Bob and Alice are marrie. When —?
ANSWER:
did they get married
Correct:
Incorrect:
It’s raining. How long has it been raining?
It’s raining. When did it start raining?
Kate is learning Italian. How long has she been learning Italian?
Kate is learning Italian. When did she start learning Italian?
I know Martin. How long have you known Martin?
I know Martin. When did you first meet him?
Bob and Alice are married. How long have they been married?
Bob and Alice are marrie. When did they get married?