[译] 我渴望收到家里的来信。
[误] I am desirable of receiving a family letter.

[正] I am desirous of receiving a family letter.
[正] I am desirous to receive a family letter.
[注] desirable 和 desirous 都可以用作表语，但 desirable 要用表示物的名词作主语，而 desirous (渴望的、想要的) 应该用表示人的词作主语。如：It is desirable to practise English with native speakers. 跟本族语的人练习英语是很理想的。