The meaning of "dear" in this context is to signify the importance of time. For example we say "Dear Vivian" at the beginning of a letter we are signifying the high importance of Vivian to us (the writer) by doing this. I think in this context it is to signify the fact that his time should not be wasted and that he needs to get to doing what he came to do. The "warning flashed" means, to me, that he needs to stop with pleasantries and get to the point; a broader context will help to clarify the meaning more. Sorry, but the context of the sentence is not enough to completely answer the question. If you want to give me a page number I can go and read enough to give a better answer to the question. Feel free to shot me a letter anytime you have more questions about the book, I do not check italki very much but I do see my e-mail everyday.

意思是宝贵的

It simply means 'very expensive'. In other words, he cannot afford to waste any time.

Hello Vivian, "that time was dear" The meaning of "dear" depends on the context,but obviously here it could mean : - important, crucial - precious -urgent requiring a speedy action or attention - intense

I think that 'dear' is a pleasant person. you like communicate with him...