One by one (idiom)

●Separately, one after the other.（逐一，逐個）

Examples:　　

1.One by one the old buildings in the city have been demolished and replaced with new high rises.　　

2.We went into the room one by one.

Keep on at sb (idiom)

●To continue to complain about or scold someone.

　　（咬住不放，糾纏不休）

Examples:　　

1.We just keep on at them until they get fed up and do something.

2.Please don't keep on at the committee. They did the best they could.

drag one's feet

●postpone doing what one should be doing;

Drag on (phrasal verb)

●If an event or situation drags on, it continues for too long.（拖拉，延遲）

Examples:　　

1.Despair grew as the war dragged on.　　

2.The history lesson dragged on for another hour.

A seven league stride (proverb)

●「七里步」，形容速度飛快。西方傳說中有一對「七里靴」（seven-league boots），穿着者一步可跨出七里之遙。此靴據說來自希臘旅行者之神荷米斯（Hermes）。這裏的league曾是歐洲通用的長度單位，相當於今天的5.556公里，今已罕用。

Pull together (phrasal verb)

●To work hard as a group in order to achieve something.（齊心協力，通力合作）

Examples:　　

1.We don't have much time but if we all pull together we should get the job done.　　

2.Everyone on our street really pulled together after the fire.