把信投入信箱

put a letter into the letterbox

把果皮投入垃圾箱

put the fruit peel in the bin

把资金投入国家建设

invest money in nation-building

投入战斗

go into battle

投入生产

go into production

投入市场

launch on the market

积极投入运动

get actively involved in the movement

以空前振奋的战斗精神投入春耕生产

launch into the spring ploughing with an unprecedented fighting spirit

一批批新油井投入生产

put group after group of new oil wells into production

她演得很投入。

She lost herself in the role.

增加对科教的投入

increase funding in science education

增加投入，切实解决实际问题

increase investment in order to effectively resolve practical considerations