祖先: ancestor, forebears...
符号: symbol, mark, sign...
侄子: brother's son, nephew...
饼: round flat cake, cookie, cake, pastry...
天文: astronomy...
笑: laugh, smile...
妈妈: mom, mother, mama...
光滑: glossy, sleek, smooth...
合并: to merge, to annex...
认: to recognize, to know, to admit...