根据句意，在答题卡标有题号的横线上，写出括号内所给单词的适当形式。

根据句意，在答题卡标有题号的横线上，写出括号内所给单词的适当形式。
小题1:His effort made the two companies reach an _____________ in the end. (agree)
小题2:These engineers __________ developed a new kind of energy saving car last year. (success)
小题3:We all felt ___________ to find out he wasn’t involved in this murder. (relax)
小题4:He has lung cancer because of ___________ second hand smoke for many years. (breathe)