问题补充：
a letter from her parents, Lily is now looking forward to from them.
A Having not received; hear B. Not received; hear
C. Not having received; hearing D. Receiving not; hearing
答案：
解析：本题考查非谓语动词。注意现在分词可以表示原因，现在分词的否定式是Not having，而不是having not。look forward to doing sth希望做某事。
