这本教科书包含了大量的练习题。

This ___textbook contains a lot of practice exercises.

课本正文比附录部分更重要。

The ___text of the textbook is more important than the appendices.

我收到了一条短信，提醒我明天有约会。

I got a ___text reminding me about tomorrow's appointment.

这个文本很难理解。

This ___text is hard to understand.