营养学家建议我国青少年要多吃奶、蛋、鱼、肉等含蛋白质丰富的食品，因为蛋白质是（　　）

    Are you able to send a letter with pictures and sounds to someone somewhere in the world without a stamp(邮票) on it? Using a computer you can send e-mails quickly and easily. The post is much slower than e-mail. E-mail can send its message to the other side of the world in seconds.

    E-mail is easy to use and it saves time and money. The differences in time in different parts of the world do not matter when sending e-mail. It's twenty-four-hour service(服务) that you can send e-mail at any time of the day or night. No one has to be there to get e-mail. It does not matter if your friends are in beds when you send e-mail to them, or you are seeing a movie at the movie theater when they send e-mail back.

根据课文默写古诗文。
①                   ，亲射虎，看孙郎。（苏轼《江城子 密州出猎》）
②《破阵子》中描写战斗场面激烈，表现义军所向披靡的句子是：                     ，                      。（辛弃疾《破阵子》）
③鲁迅具有硬骨头精神，面对御用文人的无耻攻击，虽然他们人数众多，气势汹汹，似乎“                  ”，但鲁迅无所畏惧，沉着应战，“                   ”，以犀利的杂文进行反击。（用《雁门太守行》中句子回答）
④子曰：学而时习之，             ？有朋自远方来，               ？                ，                ？（《论语》）
⑤                   ，身世浮沉雨打萍。  (文天祥《过零丁洋》)