Chen Wei isn't at school today ________ he is taking a robot competition in Shanghai.( )
A. |
so |
B. |
because |
C. |
before |
D. |
if |
Chen Wei isn't at school today ________ he is taking a robot competition in Shanghai.( )
A. |
so |
B. |
because |
C. |
before |
D. |
if |