with zest meaning in English

热情地, 热心地

He attacked the problems with zest and flair .
他用热心和能力来攻克这些课题。
He entered into our plans with zest
他热心地加入我们的计划。
He entered into the plan with zest
他热心地参加这一计划。
It was only a few days ago that he was full of contempt for the new project , but he is now working hard to with zest for its realization . what a baffling change
几天前他对这项计划还嗤之以鼻，可是他现在却以高涨的热情去努力落实这项计划，这真是让人难以理解的转变。