Used to invite, call on the listener to do an action together, or to make a gentle suggestion.1年か2年で枕をかえましょう。
Verb たり form + Verb たり form + しますN5
Expresses listing a few typical actions among many actions, often used to talk about repeated activities or not limited to only those actions.枕をあらったり、かえたりしましょう。
Dictionary form verb + と、clauseN5
Expresses an inevitable result: when the preceding action occurs, the subsequent action will certainly happen.ほこりやダニがたまると、体によくありません。