向紫色石蕊试液中加入过量的Na2O2粉末，振荡，观察不到的现象是
| A．有大量气泡产生 | B．溶液颜色先变为蓝色 |
| C．最后溶液褪色 | D．最后溶液变为蓝色 |
My friend showed me round the town, ______ was very kind of him. 
| A．which | B．that | C．where | D．it |
They use computers to keep the traffic _______ smoothly.
| A．being run | B．run | C．to run | D．running |
If you leave the club, you will not be_____back in .
| A．received | B．admitted | C．turned | D．moved |
What I need is_____ book that contains ______ABC of oil painting.
| A．a; 不填 | B．the; 不填 | C．the; an | D．a ; the |
Jenny nearly missed the flight______ doing too much shopping.
| A．as a result of | B．on top of | C．in front of | D．in need of |