So much so he taught himself French and English all by the age of 6.

所以在6岁是就开始自学法语和英语。

By the age of 14, he was fit enough to pose for anatomical charts.

在十四岁，经够健壮到能当人体结构图的模特儿。

By the age of three, he was able to read.

到三岁，经识字。

Each Indian of the Great Plains could ride a horse by the age of five.

大平原地区的每个印第安人五岁就开始骑马。

This give-and- take allows them to use fluent sentences by the age of four.

这种“输入并输出”的方法让人类儿童在四岁就能使用流利的子。

The actor achieved fame by the age of 22.

那位演员22岁就成名。

For both girls and boys, it is usually complete by the age of 18.

无论男孩子还是女孩子，通常都是到 18 岁完成（青春期）。

Baldness affects approximately half of men worldwide by the age of 50.

全球大约有一半的男性在50岁秃顶。

By the age of sixteen, Frank had ditched school altogether.

法兰克16岁的候就辍学。

He had mastered both integral and differential calculus by the age of 15.

在15岁就经掌握微积分。

By the age of twenty-five, I had managed to get married ... and also divorced.

25岁，我不仅完成结婚这件大事，也经历离婚。

Blood tests indicate that most children have had it by the age of 5.

血液测试表明，大多数儿童在5岁就患有此病。

By the age of 14, he was playing internationally.

到14岁，开始在国际上下棋。

For both sexes, it is usually complete by the age of eighteen.

男孩和女孩通常在18岁结束青春期。

Do you know he was a multimillionaire by the age of 35?

你道在35岁经是千万富翁吗？

By the age of seven, children are capable of thinking in abstract terms.

【abstract】儿童到七岁就具有抽象思维的能力。

One patient, who began puberty blockers aged 12, suffered four fractures by the age of 16.

一名患者在12岁开始服用青春期阻断剂，16岁发生四次骨折。

By the age of 12 nearly every child has a phone, according to research in Britain.

英国有研究表明，到12岁，几乎每个孩子都拥有一部手机。

The study challenges the commonly held notion that intelligence is 'static' by the age of about 18.

人们普遍认为，智商到18岁左右就“静止”，此研究否认这个说法。

By the age of three, a child's brain has twice as many synapses per neuron than in adults.

到三岁，儿童大脑中每个神经元的突触数量是成年人的两倍。