You__C_read this book if you don't want to.=== You don't have / need to read this book if you don't want to.
因为这里强调的是必要性,所以用needn't
强调许可性,我们用mustn't.
强调能力,我们用can't
You__C_read this book if you don't want to.=== You don't have / need to read this book if you don't want to.
因为这里强调的是必要性,所以用needn't
强调许可性,我们用mustn't.
强调能力,我们用can't