shū bāo / lǐ / yī dìng / yào / bèi / yī / píng / xiū zhèng yè / kǎo shì / shí / hěn / yǒu yòng

书包里一定要备一瓶修正液，考试时很有用。

You must keep a bottle of correction fluid in your schoolbag; it's very useful during exams.