Question

【题目】You won’t find it difficult ______ you have mastered it.

A. before B. while

C. once D. though

Answer 1

【答案】C

【解析】考查条件状语从句。A. before在……之前；B. while当……的时候；C. once一旦；D. though尽管。句意：一旦你掌握了它，你就不会觉得它很难了。故选C。