分类：教育/科学-升学入学-中考
问题：一个选择题1.
1.-You'd better a Mr. Wang for help when ________ problems.-I see,but I 'm not sure when ______ time.A.you have; to have    B.having; he has C.to have;he has       D.to have;has he 请问：正确答案是什么？ 另分析第一句的句子结构，when 后是什么用法？
回答：1.-You'd better ask Mr. Wang for help when ________ problems. 
-I see,but I 'm not sure when ____B__ time. 
A.you have; to have B.having; he has 
C.to have;he has D.to have;has he 
现在分词作定语。时态保持一致.