________ of my sisters are experts in agriculture. Helping the farmers improve their farming techniques _________their duty.

Come and play together with us, Henry.—No, I’m making my plan _the new term.[ ]

Do you often play computer games? —No, And so do ________ of my classmates, you know we are very busy

The station is the factory. [ ]

I’d prefer ______ in the office rather than ______ at home watching TV.