POINT

Don't confirm it by email, do it by phone to be 100% sure.

Send out the invitations by email.

 

用途

byに名詞の単数形で方法や手段を述べる

基本はaやmyのような限定詞はつかない

 

*seniority (先輩であること)

*by seniority (年功序列で) = by number of years