Yabla video uses of 课本

yuè
kàn
他们的 tāmende
课本 kèběn
jiù
yuè
紧张 jǐnzhāng
I am getting nervous by looking at their textbooks.
因为 yīnwèi
老师 lǎoshī
那儿 nàr
课本 kèběn
shì
yǒu
标准 biāozhǔn
答案 dá'àn
de
because our teachers and textbooks already had the standard definition of such.