The actor achieved fame by the age of 22.

那位演员22岁时就成名了。

By the age of 14, he was playing internationally.

到14岁时，开始在国际上下棋。

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

到三岁时，识字了。

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

法兰克16岁的时候就辍学了。

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

全球大约有一半的男性在50岁时秃顶。

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?

你知道在35岁时是千万富翁了吗？

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

在15岁时就掌握了微积分。

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

【abstract】儿童到了七岁就具有抽象思维的能力。

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

在十四岁时，够健壮到能结构图的模特儿。

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了。

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

这种“输入并输出”的方法让类儿童在四岁时就能使用流利的句子。

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）。

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

25岁时，我不仅完成了结婚这件大事，也历了离婚。

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岁时就患有此病。

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五岁就开始骑马。

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

一名患者在12岁时开始服用青春期阻断剂，16岁时发生了四次骨折。

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岁时，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.

们普遍认为，智商到了18岁左右就“静止”了，此研究否认了这个说法。

He was the youngest of 7 children and by the age of 5, he was already composing music.

是7个孩子中最小的一个，5岁的时候，就开始作曲了。