选择正确的语句表达,将其序号填入题前括号里。
(    )1.
A. We have three new teachers.
B. We have two new teachers.
C. We have two new pupils.
(    )2.
A. Sit in the first row, please.
B. Sit in the second row, please.
C. Sit in the third row, please.
(    )3.
A. I'm Chinese.
B. I'm Canadian.
C. I'm American.