２語を組み合わせて名詞を修飾する場合、ハイフンでつなぎます。（名詞を修飾しないときはハイフンでつなぎません）
○ This is not a user-friendly system.
× This is not a user friendly system.
× This system is not user-friendly.
○ This system is not user friendly.
ただし、"-ly"で終わる副詞が前にくる場合はハイフンを付けません。
× They have a beautifully-designed logo.
○ They have a beautifully designed logo.
