sing renewable energy is a simpleidea, but ______ we find it hard to put into practice.

There is a police car _____ the bus. The police are watching the traffic.

_______of personal taste

Jack descried his father,who ____abrave boy many years ago, as a strong-willed man.[ ]

I saw the Smiths at West Beijing Station this afternoon.— You __________. They are still on holiday in Hawaii.