题目选项分析

Coffee prices rose sharply Monday, posting their biggest one-day gain in almost three years, after a weekend cold snap in Brazil raised concern that the world's largest crop could be damaged at a time when supplies are already tight.

Coffee prices rose sharply Monday, posting their biggest one-day gain in almost three years, after a weekend cold snap in Brazil raised concern that the world's largest crop could be damaged at a time such as when supplies are already tight.