Trade frictions between the two countries had been caused by trade protectionists.

两国间的贸易摩擦是由贸易保护主义者引起的。

Alicia was a jeweler by trade.

艾丽西亚是个珠宝商。

He was a carpenter by trade.

他以木工为业。

He was a printer by trade and naturalist by avocation.

他在印刷厂工作，同时是个博物学爱好者。

He is a butcher by trade.

他的职业是屠夫。