问题补充：
Welcome to our store! We all our things at good prices.
A. know
B. think
C. sell
D. buy
答案：
A. know
B. think
(答案→)C. sell
D. buy
解析：句意：欢迎来我们店！我们以便宜的价格出售所有的东西。A. know 知道； B. think 认为；C. sell 卖，出售；D. buy买。根据Welcome to our store!可知此处是商店，因此商店要卖东西。故选C。
