This means two things happen at the same time. One change happens, and then another change happens with it.
Verb [dictionary form] + とともにPrimary
Noun + とともにPrimary
い-Adjective + とともに
な-Adjective + である + とともに
This means two things happen at the same time. One change happens, and then another change happens with it.
経済が発展するとともに、環境問題が深刻になった。
As the economy developed, environmental problems became serious.
年齢とともに、物忘れがひどくなる。
With age, one's forgetfulness gets worse.
収入が増えるとともに、必ずしも幸福度が増すわけではない。
As income increases, happiness does not necessarily increase as well.
卒業とともに、友人たちと離れ離れになった。
Upon graduation, I became separated from my friends.
インターネットの普及とともに、人々のコミュニケーションの仕方も大きく変化してきている。
With the spread of the internet, the way people communicate has also been changing greatly.
This phrase has two main uses. It can show that two things change together. Like when the times change, ideas also change. It can also mean 'together with' someone. Or 'at the same time as' an event. You can tell the meaning from the rest of the sentence.
This is different from "~ni tsurete" and "~ni shitagatte". Those mean one thing changes slowly with another. "~to tomo ni" can show changes that are not slow. It can also mean two things happen at the same time. Only "~to tomo ni" can mean "together with" someone or something.
Don't use this when you talk to friends. It sounds too formal. For example, don't say "I went to the store with my friend" using this grammar.
Contrasts with(1)
More formal alternatives(3)
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