向小千老师学习，也给小千块豆腐

I learned something from your recording, esp. the pronounciation of the sound /u/ in word "two". Thank you.
Here's my comments on the last sentence in your recording, it seems to me a little strange. I assume that you might pronounce that way for emphasis purposes.

第七句有两个地方你的录音值得商榷:
es 作为复数后缀在/-s/读/-iz/,  prices /-siz/。 而你的录音读的是/ -sis/。 （纯粹鸡蛋里挑骨头）。
由副词'up', 'out', 'away', 'off' 等组成的副词词组，这些副词在句么通常重读。你的录音gone是重读。

About“7 The prices of textbooks have gone up.”

'-es' as plural suffixes added to words ending with 's' is pronounced as /-iz/, like prices /-siz/

Small adverbs like 'up', 'out', 'away', 'off' etc usually do not take stress in sentences unless for emphasis purposes, however,  they do in most cases take a stress while they are at the end of a sentence. Take those adverbial phrases for example:

wake them UP
read it OUT
cover him UP
take them AWAY
use them UP
put it ON
has gone UP