宾语从句can you think what his job is?这里可以说成can you think what is his job?

不能.宾语从句中要使用陈述语气.如果从句部分是特殊疑问句,可以把助动词放在陈述语气的位置上,一般疑问句可以用if或whether来构成从句.
如：I don't know what I can do.(what can I do?)
Do you think if she is a student?(Is she a student?)