The cave can only be reached by boat. 这个山洞只有乘船才能到达。
表示“到达”时,通常为及物动词,但后接 here, there, home 等副词时,它是不及物动词。如:
It was late afternoon before he reached home. 傍晚时候他才到家。
I reached here Thursday morning. 我星期四早上到达这里的。
They reached there yesterday, where a negotiation of sale will be held. 他们昨天抵达那里,有一个关于销售的谈判在那儿举行。
至于是否可以用于被动语态,那要看需要。若语义需要,也完全可以的。如:
Some of the beaches can only be reached by boat. 其中有些沙滩只有坐船才能到达。