①若 $a\parallel b$ ， $b\subset \alpha$ ，则 $a\parallel \alpha$ ；

②若 $a\parallel \alpha$ ， $b\subset \alpha$ ，则 $a\parallel b$ ；

③若 $a\parallel b$ ， $b\parallel \alpha$ ，则 $a\parallel \alpha$ .

其中正确命题的个数是（   ）

各种形式的能量在一定的条件下都可以相互转化．水电站里的水轮机带动发电机发电， ____能转化为 ____能；电动机带动机器转动， ____能转化为 ____能；植物吸收太阳光进行光合作用， ____能转化为 ____能；燃料燃烧时，燃料的 ____能转化为 ____能，也就是通常所说的要放出 ____

    We use the Internet for many things: business, shopping, writing letters, talking to people, finding information, and so on. In recent years, a new kind of English has grown on the Internet. There's no real word for it yet, so we'll call it e-talk. People don't like typing too much. To save time, they turn phrases (短语) into a few letters called acronyms(首字母缩略词). Acronyms are often used in chat rooms.
Some of them are:
BTW(by the way)     BRB (be right back)
LOL (laughing out loud) IMO (in my opinion)
People also use many abbreviations. They are shortened forms of words. Some common abbreviations are:
info (information)    puter (computer)    pic (picture)      sec (second)
We usually don’t see people when we communicate on the Net, so people have new ways to show feelings. Most people use their keyboards to draw “feeling”, such as:
: ) (happy)     :-( (sad) ;    : P (joking)   : O (surprised)
These days, many forums have picture feelings. For example:
happy          sad         angry        cool
There are even whole new words, like ‘newbie’ (someone who is new on a chat board or forum). When you write something bad about someone else, it’s called ‘flaming’ the person.
It takes time to get used to e-talk. Also, different groups in the Net have their own special ways of communicating. Newbies sometimes have to ask other people what they mean. As the Internet grows, e-talk will continue to grow and change.