Question

I didn't understand ________, so I raised my hand to ask.

1. A.
   what my teacher says
2. B.
   what does my teacher say
3. C.
   what my teacher said
4. D.
   what did my teacher say

Answer 1

C
考查宾语从句的用法。宾语从句用陈述语序，由此可排除选项B、D。主句用的是一般过去时态，从句要用相应的过去时态。故选C。