By the 1930s the wristwatch had almost completely supplanted the pocket watch.

到了 20 世纪 30 年代，手表几乎完全取代了怀表。

《柯林斯英汉双解大词典》

However, this purely visual system was useless in bad weather, and, by the 1930s, radio communication was coming into use for ATC.

然而，这种纯粹的视觉系统在恶劣天气下毫无用处，到了20世纪30年代，无线电通信开始用于空中交通管制。

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By the 1930s Shanghai was among the ten largest cities in the world.

1930年代，上海是世界十大城市之一。

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By the 1930s, under the chairmanship of Ernest Oppenheimer, De Beers' cartel had near total sway over the trade.

FORBES: Fracture Lines

By the 1930s, the median life expectancy had increased to about 59 years.

FORBES: Fixing The Nagging Problem Of Social Security

By the 1930s, Lanvin was focusing more on her womanswear, and eventually she stopped making clothes for girls and boys.

FORBES: Lanvin Petite: Are Designer Clothes For Children Really That Nefarious?