Sam enjoys ___ stamps.
. He always_________his time and his efforts .
. .She asked Mary_________her homework.
. The couple accepted the present sent by the man_________their kindness.
. .— Come on, please give me some ideas about the project. — Sorry. With so much work_________ my mind, I almost break down.
. A survey of the opinions of experts_________that three hours of outdoor exercise a week _________good for one’s health.