It is said that the early European playing-cards ______ for entertainment and education.[ ]
A. were designed
B. have designed
C. have been designed
D. were being designed
要到微信小程序或APP查看答案哦。
实在点不开答案,可以分享到微信,
在微信里面查看答案。
APP具体操作流程为:
--- How about going for a picnic this coming Sunday?
--- _________, but I have to see my grandma with my parents.
A.All right
B.Sounds great
C.No problem
D.No, I’m sorry
维生素B2的特点不包括()
A.在碱性环境中稳定
B.对光敏感
C.黄素酶类的辅酶成分
D.在体内催化氧化-还原反应
E.缺乏可致眼-口腔-皮肤的炎症反应
固定化葡萄糖异构酶被用于玉米糖浆的生产,它的作用是()。
A、将果糖异构成葡萄糖
B、将半乳糖异构成葡萄糖
C、将葡萄糖异构成果糖
D、将甘露糖异构成葡萄糖
医院感染乙型肝炎、丙型肝炎由何途径引起?
计算题:如果Cu在钢液中含量为0.3%,实验测得在1540℃时,Cu溶于Fe中时K=53Pa,问真空度为2.67Pa时,钢液中的Cu能否蒸发?