题干
Mike is my good friend. He is ________ American boy.
A：a
B：an
C：the
D：/
答案(点此获取答案解析）
B
Mike is my good friend. He is ________ American boy.
A：a
B：an
C：the
D：/
通过，充放电的化学方程式为 2Na2S2+NaBr3
Na2S4+3NaBr。