It would be great if you could get back in shape in time for the World Cup.
重点
It would be great...在对话中表示“……(真是)太好了”。if you could get back...the World Cup是由if引导的条件状语从句。
in shape的意思是“处于良好状态”,用于指人时特指“体态健美或身体状况良好”。如:
You'll never be in shape until you eat less and take more exercise. 只有少吃多锻炼你才能保持体形健美。
in time for sth. 的意思是“及时赶上某事物”。如:
I arrived just in time for the meeting. 我刚好及时赶上了开会。