・fight with an enemy 敵と戦う.

・vie with each other 互いに競う.

・be at war with ⇒at WAR.

・contend [compete] with… …と競争する.

・grapple with… …と組打ちする.

10 [器具・手段] …で, …を用いて (by the use of) (cf. by^１ 1).

・cut a branch with a knife ナイフで枝を切る.

・write with a pen ペンで書く (cf. in 12).

・We see with our eyes, and hear with our ears. 目で見, 耳で聞く.

・I have no pen to write with. 書くペンがない.

・I have no money to buy it (with). それを買う金がない.