Mom,whereisDavid?Heisworking
问题详情：
Mom, where is David? He is working ____that difficult math problem.
A. for B. with C. on D. in
【回答】
C
知识点：介词和介词短语
题型：选择题
问题详情：
Mom, where is David? He is working ____that difficult math problem.
A. for B. with C. on D. in
【回答】
C
知识点：介词和介词短语
题型：选择题
