5. He panted heavily after running.
他在跑步之后重重地喘着气。
还能这样说：
After running, he panted for breath.
He gasped for breath after a run.
应用解析：
pant out one's last words 气喘吁吁地说出遗言；
pant for freedom 渴望自由；
pant along 气喘吁吁地走或跑
6. I run like a streak of lightning.
我跑起来快如飞。
还能这样说：
I run like flying.
I run very fast.
应用解析：
blue streak 迅速移动的事物；
go like a streak 飞跑；
have a streak of 有……的气味；
winning streak 连胜
7. Running is a healthy exercise.
跑步是一项健康的运动。
还能这样说：
If you run every day, you'll get healthier.
People become healthy by running every morning.
应用解析：
in poor health 健康情况不佳；
broken in health 身体搞垮，体弱多病；
propose the health of sb. 提议为某人健康干杯；
recover one's health 恢复健康
8. You're too fat; go and run off your excess pounds.
你太胖了，要跑跑步减减肥。
还能这样说：
You are overweight too much, and you should run to get slim.
You are overweight, try and run off all those excessive pounds.
谚语：
The fat is in the fire.
木已成舟。