_______ on time, this medicine will be quite effective.
—It's nice.Never before ________ such a special drink!—I'm glad you like it.
The police were seeking more information to find out ________ the rich merchant.
Only when he reached the teahouse ________ it was the same place he'd been in last year.(2011·全国Ⅰ)
Try ________ she might, Sue couldn't get the door open.(2011·全国Ⅰ)
The newly published book, which refers ________ basic English grammar, is ________ only for beginners.