However,my enthusiasm waned. The time I spent at exercises gradually diminished. Little bylittle the eleven minutes fell to zero.

　　19.However, my enthusiasm waned.

　　而这时我的热情却减退了。

　　20.The time I spent at exercises gradually diminished.

　　我花在锻炼上的时间逐渐减少。

　　语言点:spend at/on sth.的意思是“花费…在某事上”。

　　21.Little by little the eleven minutes fell to zero.

　　慢慢地从11分钟减到了零。

　　语言点:Little by little的意思是“慢慢地”。