问题补充：
In winter people usually keep flowers in their houses to them from the cold.
A. produce
B. provide
C. protect
D. plant
答案：
A. produce
B. provide
(答案→)C. protect
D. plant
解析：A. produce生产 B. provide提供 C. protect保护 D. plant种植；句意：冬天人们常常把花放在房子里防止它们被冻死。protect sb from sth/doing sth保护某人或是物免受…，故选C
