well-known to us all that knowledgeis __ treasure, but practice is ___ key to it.

Rarely ______ so heavily in Ning Xia as it did in Hei Long Jiang last year.

The question why Cheng Yu chose to return to his hometown from abroad made him feel lost and as if he didn’t ________ here.

He warned me of what I otherwise __________ about the accident.

Tom as well as his parents ______ going to Japan next week.