That piece of music sounds quite familiar. Who ________ the piano upstairs?[ ]

He was hiding behind the door _________ hecould see what was happening

Thesportsmeetwillbe____nextweekbecauseofthebadweather.

“Shall Mary come and play computer games?” “No, _______ she has finished her homework.”

Would you like to climb mountains with me this Sunday—I’d love to. But I _______ play table tennis against Class Three.