As soon as his teacher begins lecturing, he begins to doze off, not intentionally but _____.

All the travelling fare, unless specifically stated _________, includes admission charges to the attractions, shows and exhibitions we visit.

I have never fallen for this kind of trick. Even though you didn’t lie, it didn’t mean you were ______.

 The repair work may take us a long time，but          it’s worth trying.

____ the search engine just gave me some brief introductions rather than the whole content of the book to read.