be in good spirits!

Idiom: "(to) be in good spirits" 

Definition:

happy; in a good mood

Examples:

1) After his successful surgery, Sam was in good spirits.

2) Dave was in good spirits after he received an A on his paper.

中文解释： http://www.youzienglish.com/main/idiom_of_the_day/to_be_in_good_spirits/cn/