下列说法正确的是
| A．明矾和漂白粉常用于自来水的净化和杀菌消毒，两者的作用原理相同 |
| B．用PH试纸测得氯水的PH约为3 |
| C．纯净的H2在Cl2中安静的燃烧，发出苍白色的火焰，集气瓶口有白烟生成 |
| D．氯气能与水反应生成次氯酸和盐酸，久置氯水最终变为稀盐酸 |
Charles was alone at home, with_______ looking after him.
| A．someone | B．anyone | C．not one | D．no one |
It is often ______ that human beings are naturally equipped to speak.
| A．said | B．to say | C．saying | D．being said |
I’m sure that your letter will get______ attention. They know you’re waiting for the reply. 
| A．continued | B．immediate | C．careful | D．general |
All the dishes in this menu, ______ otherwise stated, will serve two to three people. 
| A．as | B．if | C．though | D．unless |
The children loved their day trip, and they enjoyed the horse ride ______.
| A．most | B．more | C．less | D．little |