—Have you seen _______ pen?I left it here this morning.
—Is it _______ black one?I think I saw it somewhere.
A.a,the B.the,the C.the,a D.a,a
答案：A
前面一空是首次提到,所以用a,第二空意思是“是黑色的那支吗”,是特指,所以用the.
The students were ____ over the ____ problem,listening to the teacher with a ____ expression on their faces.
A.puzzled; puzzling; puzzling B.puzzled; puzzling; puzzled
C.puzzling; puzzling; puzzled D.puzzling; puzzled; puzzling
答案：B
puzzled 表示“感到迷惑的,茫然的”,修饰人,而puzzling 表示“令人迷惑的”,修饰物.所以正确答案是B.