n. soft fine feathers
n. (American football) a complete play to advance the football
n. English physician who first described Down's syndrome (1828-1896)
n. (usually plural) a rolling treeless highland with little soil
a. 向下的
adv. 下, 下去, 降下
prep. 往下, 沿着
n. 丘陵, 软毛, 开阔的高地
[计] 向下, 退下命令