下列物品中应用凸透镜成像原理的是( )
A.放大镜
B.平面镜
C.潜望镜
D.近视眼镜
放大镜是利用凸透镜工作的;平面镜和潜望镜是利用平面镜工作的;近视眼镜是利用凹透镜工作的.
故选A.
Lucy liked all the dresses there, but she took the ______one to save as much money as
possible for Project Hope.
A.cheaper
B.more expensive
C.cheapest
D.most expensive
下列化合物中能使Kedde试剂产生阳性反应的为( )
A.黄酮苷
B.洋地黄毒苷
C.甘草皂苷
D.香豆素苷
E.生物碱