run in

片語動詞所屬單字run

run in — 片語動詞

1. To use a new engine or machine gently for a period so it works well later.

1.片語動詞
釋義

磨合

To use a new engine or machine gently for a period so it works well later.

例句

You should run in a new car engine for the first 500 miles.

The mechanic said to run in the lawnmower slowly.