A:have you been to Shanghai to visit the World Expo
B:Where was the 16th Asian Games held
C:if you were going to Xi’an to visit the Horticultural Exposition (园艺博览会)
D:When will you go to Xi’a
如图,在正方形ABCD中,E为CD边上一点,F为BC延长线上一点,CE=CF,∠FDC=30°,求∠BEF的度数.
两栖动物的幼体和成体分别生活在( )
有了医生和护士的合作,才能完成精密的手术;有了老师和学生的教学相长,学习生活才能紧张有序。这说明( )