3. The student began to nod off during math class. 那学生上数学课的时候开始打盹。
英英解释
n.
1. a sign of assent or salutation or command
2. the act of nodding the head v.
1. express or signify by nodding
2. lower and raise the head, as to indicate assent or agreement or confirmation
3. let the head fall forward through drowsiness
4. sway gently back and forth, as is in a nodding motion
5. be almost asleep