What is our head teacher like do you know?Oh he is very kind he looks very seri

问题补充：

--- What is our head teacher like, do you know?

--Oh, he is very kind, he looks very serious.

A. because

B. though

C. if

D. when

答案：

A. because

(答案→)B. though

C. if

D. when

解析：句意：尽管他看起来很严肃，但他很善良。A因为B尽管，虽然C如果D当。故选B。