观察微小的生物个体时，要根据实际情况选择使用放大镜或显微镜。

①长征精神对中国人民争取民主革命的最后胜利起到了巨大的鼓舞作用 ②长征途中召开的遵义会议，标志着***从幼稚走向成熟 ③长征实现了***工作重心由农村到城市的转移 ④长征撒下了革命火种，成为人民革命战争取得胜利的可靠保证

读右下图，分析下列说法正确的是
 

如图所示，分别用甲、乙两个滑轮组在相等时间内将质量相等的重物匀速提升相同的高度，绳和轮之间的摩擦均不计，下列说法正确的是（　　）

    We are all learning English, but how can we learn English well? A student can know a lot about English, but maybe(可能) he can't speak English. If you want to know how to (如何) swim, you must get into the river. And if you want to be a football player, you must play football.
So, you see. You can learn English only by(通过) using(使用)it. You must listen to your teacher in class. You must read your lessons every day. You must speak English to your classmates and also you must write something sometimes. Then one day, you may find your English very good.