分别取四种溶液于四支试管中进行实验，结论正确的是
| |
操作 |
现象 |
结论 |
| A |
加入浓NaOH溶液，加热 |
湿润的红色石蕊试纸变蓝 |
原溶液中一定含有NH4+ |
| B |
加入稀盐酸，将产生的气体通入澄清石灰水中 |
溶液变浑浊 |
原溶液中一定含有CO32- |
| C |
加入少量双氧水，再加几滴KSCN溶液 |
溶液变红 |
原溶液中一定含有Fe2＋ |
| D |
加入BaCl2溶液，再加入稀硝酸 |
有白色沉淀生成 |
原溶液中一定含有SO42- |
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 |
The CDs are on sale! Buy one and you get ______ completely free.
| A．other | B．others | C．one | D．ones ks |