已知$\left|\overrightarrow{OA}\right|=\left|\overrightarrow{OB}\right|=1,\angle AOB=\frac{2\pi }{3},\overrightarrow{OC}=\overrightarrow{OA}+2\overrightarrow{OB}$,则$\overrightarrow{OC}$与$\overrightarrow{OB}$夹角为（  ）

词汇运用 用所给词的适当形式填空
⑴Thank you for____ on them on the plane. (operate)
⑵I thought of my good friend when I read your____ (advertise)
⑶We should help all children to get an____   at school. (educate)
⑷His father died because of____ (ill).
⑸The old man is ____  to the policeman. (grate)
⑹I was made____ (read) the text once more by Miss Chen.
⑺I think I should Share his ____ when he is sad. (happy)
⑻He says that he wants to be a____ (fly) doctor when he leaves school.
⑼I don't know what made him laugh so____ (excite)?
⑽My watch doesn't work. It needs to____  (repair).
⑾Coffee ____  by most Chinese people. (not drink)
⑿He spend his spare time____  watching TV. (most)
⒀The car was one of the ____ . (run)
⒁ORBIS is one of the____  in the world. (charity)
⒂Many people in poor area don't have enough money for____  treatment. (medicine)

油菜的结构层次是（　　）