玉石是指那些自然界产出的,具有()的单矿物或多矿物集合体。
A.耐久、稀少和工艺价值
B.美观和工艺价值
C.美观、耐久、稀少
D.美观、耐久、稀少和工艺价值
参考答案:D
— You’ve won the football game. Congratulations!
— ____.
A.It’s nice of you to say so
B.We are really lucky
C.No one else could do it
D.Oh, not really
分别说明氮肥在旱地施用时,氮素损失的途径有哪些?提高氮肥利用率的相应措施是哪些?