She _____ an English teacher. [ ]
A. uses to
B. used to
C. use to be
D. used to be
答案:D
依题意画图,并求∠DPF的大小.
(1)作∠AOB=60°;
(2)点P在∠AOB内部,过P点作PE∥OA交OB于E点;
(3)过P点作PF∥0B交OA于F点;
(4)过P点作PD⊥OA,垂足为D点;
(5)求∠DPF的大小.
对过分乐观的研究表明,许多积极情感和积极的认知常同时产生,很难确定是认知产生情感还是情感产生认知。