定期献血者是指至少献过()次血并保持每年至少献一次血的人。
C
暂无解析
早产儿体重低于哪项应放入暖箱（）
Ifyou_______inbehavinginthiswayyouwillbringyourselfnothingbuttrouble.
Whatarethecharacteristicsofgoodwritings?
Copernicusmaintainedthattheearth_____roundthesun.
Theboycomplained_______apaininhisstomach.
