For kids of this age, two hours of sitting in a classroom ________ too long.
Today,computers are really helpful.They________everywhere.
A year has four seasons and it________twelve different star signs.
Battery-operated slippers are used________seeing in the dark.
The children________not to play with fire.
The Northern Tower of Xin Hua has a long history.It________in 1835. A.is built B.was built C.was building