3d风景图片:What subject did you specialize in 是什么意思?

What subject did you specialize in 是什么意思? what temperature did penguin live? what you did and said what did you have for breakfast? what did you have for lunch? what did you have for dinner? What he did not____what we had expected. what did you mean by saying 是什么意思 what did she teach again?是什么意思？ What did Susan say just now? 4Did you notice what the traveler___? what did they do over the weekend ?