某英文杂志Help栏目Conversation with Mr. Helper的负责人Mr. Helper收到新华中学李磊的一封来信，仔细阅读下面的来信，根据提示，帮助Mr. Helper写一封回信。

Dear Mr. Helper，

I'm a student from Xinhua Senior High School. I have some difficulty in my English reading comprehension.

Though I practice reading a lot every day, I make no progress. I feel very depressed. I would be grateful if you could give me some advice.

Yours sincerely，

Li Lei

内容要点：

注意：1.词数100左右；

2．可适当增加细节，以使行文连贯；

3．信的开头和结尾已为你写好。

刺激要达到一定的_________、_________和____________才能引起机体产生反应。