东南亚地区古时称南洋，是华侨的集聚地，华侨去南洋谋生最早可追溯到 [ ]
A、汉朝
B、三国
C、唐朝
D、明朝
答案：A
It's wonderful to hike with Dad and I have felt _____ with him. [ ]
A. to protected
B. protected
C. protecting
D. to be protected
已知|a|=1，|b|=6，a·（b-a）=2，则向量a与向量b的夹角是（）
