断面深黄色、纤维性，呈裂片状分层的药材是( )
A．地骨皮B．牡丹皮C．杜仲D．黄柏E．桑白皮
参考答案：D
莹石在电弧炉炼钢中炼钢中既能改善炉渣的流动性，又能提高炉渣的碱度。
When Lily came home at 5 p.m. yesterday, her mother（）dinner in the kitchen.
A.cooked
B.was cooking
C.cooks
D.has cooked
