Question: My knees buckled on the stairs. What is the effect?

Answer: I caught myself on the railing.

Question: I lingered in bed upon awakening. What is the cause?

Answer: It was Saturday.

Question: The chair squeaked. What is the cause?

Answer: The man scooted the chair closer to his desk.

Question: The woman's purse was missing. What is the cause?

Answer:
She left it unsupervised.