Learning without thought is labor lost; thought without learning is perilous.
学而不思则罔，思而不学则殆
We must always think about what we learn.
我们必须不时思考我们之所学。
Learning without understanding is a waste of time。
学习而不明其意是浪费时间。
Likewise, ideas that are not based on actual knowledge are dangerous things as they may mislead us or others.
同样地，不根据实际的知识而得来的思想是很危险的，因为这些思想会误导我们自己，也会误导他人。
As Confucius said,
子日：
"Learning without thought is labor lost; thought without learning is perilous. "
“学而不思则罔，思而不学则殆。”