prep. 被, 经, 由, 在...之旁ad. 经过, 在近处相关词组: by far... by and by by and large
◆记忆方法一：
词根词缀记忆法：by work副业（by+work工作）,by-表示"在旁边，副的"
◆记忆方法二：
by prep. 在……旁,靠近;被,经,沿,通过;不迟于,到……时为止;根据;靠,用ad. 在近旁,经过
解析：by作为词根意思是副、旁的、次要的,例如:bypass 旁道 bypasser 经过的人 byproduct副产品
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By和Before的用法区别
今天档源英语学习网小编给大家说一下by与before在表达时间方面的区别吧。
by表示不迟于某一点时间（可能是现在，也可能是过去），包括了那一点。例如：
You'd better come back by 8'o clock.
He had finished the work by ten o'clock this morning.到今天上午十点钟, 他已完成了这项工作。
By与before都可以做介词与副词，但是Before还可以做连词，当两者都表示在－－－－之前这意思时候，By的词性只能是介词，而Before三种词性都可以用来表达。简单点说，By在表示在－－之前，只能表示在某个时间点之前，而且已经非常接近这个时间点，而Before离这个时间点，还很长。
China plans to expand its high-speed railway network to 50，000 km by 2020, to cover almost all large and medium-sized cities.
by/till(until)
I'll be back by 5 o'clock.我最迟五点回来。
I'll stay here till next month.我要在这待到下个月。
<辨析>这两面三刀个词都可解作“到......时为止”。by 是介词，含有“不迟于，在......时之前”的意思(=not later than)，用来谈将来某一时刻会发生或在此以前会发生的动作，含有过去完成时态的句子也常用到它。如：
By daybreak the fisherman had cast his net three times.拂晓前渔夫已撒网三次。
till(until) 含有“直到......之时”的意思，用来谈目前正在进行而将来某一时刻将停止的事情或情况，它既可用作介词也可用作连词。如：
They will go on working till dawn.他们将继续干到天亮。
I'll wait here till father comes back.我要在这里一直等到父亲回来。
She enjoys herself by reading novels.
读小说对她来说是一种享受。
This cup can measure fluids by the half litre.
这个杯子能量半升液体。
N-COUNT. 交通阻塞;堵车. A traffic jam is a long line of vehicles that cannot move forward because there is too much traffic, or because the road is blocked by something.
In the evening we watched the sunset by the beach.
傍晚我们在沙滩边看日落。
I came back by bus.
我是乘公共汽车回来的。
※There are only two powers in the world, the sword and the pen; and in the end the former is always conquered by the latter. 世界上只有两种力量∶刀和笔；而其结果，后者总是战胜前者。
※The dullard's envy of brilliant men is always assuaged by the suspicion that they will come to a bad end.——Sir Max Beerbohm, British writer笨人对聪明人的嫉妒常因“他们不会善终”的猜测而得以减弱。英国作家 毕尔博姆爵士 M
※The horizon of life is broadened chiefly by the enlargement of the heart.——H.Black American writer生活的范围是随着心胸的开阔而变宽广的。美国作家 布莱克,H.
※The world can be changed by man's endeavor, and that this endeavor can lead to something new and better .No man can sever the bonds that unite him to his society simply by averting his eyes . He must ever be receptive and sensitive to the new ; and have sufficient courage and skill to novel facts and to deal with them . (Franklin Roosevelt , American President )——人经过努力可以改变世界，这种努力可以使人类达到新的、更美好的境界。没有人仅凭闭目、不看社会现实就能割断自己与社会的联系。他必须敏感，随时准备接受新鲜事物；他必须有勇气与能力去面对新的事实，解决新问题。(美国总统 罗斯福建. F.) "
