（１）副詞節中（副詞節のWhen節，If節など）の「主語＋be動詞」は丸ごと略せる。 ・When you are in Rome, do as the Romans do. →When in Rome, do as the Romans do.「郷に入っては郷に従え」 ・When I was young, I… →When young, I… ・While you are in…