片語

"stumbling block"（名詞片語）是指一個會阻撓後續進程或目標的問題。
Let's figure out what stumbling blocks we might run into.
Resistance from management might be a stumbling block to an agreement.

"rest assured"（動詞片語）是用來告訴某人某件事是真實的，且不需要煩惱。"rest assured" 後面要加上 ("that") + S + V。"that" 則可有可無。
There is no fog at Heathrow Airport, so we can rest assured that we will land in London on time.
You can rest assured that we want to acquire companies that we can grow.

"track record"（名詞片語）是指某個人或某件事成功或失敗的表現記錄。
We only seek out companies that have an impressive track record.
I'm not sure we should use that airline since it has a pretty bad track record. 

"put in writing"（動詞片語）表示將某事正式列入文件中。"put in writing" 要與受詞合用，受詞通常置於 "put" 和 "in writing" 之間。
I'm not sure that we can put any guarantees in writing. 
The offer isn't official until they put it in writing.