小麦拔节期50%以上植株主茎第一节离开地面（）
A.0.5－1CM
B.1－1.5CM
C.1.5－2CM
D.2－2.5CM
参考答案：C
______he was tired,______he didn’t stop______.
A．Although ; but; to rest
B．/; but; to work
C．Although;/; rest
D．Although;/; working
生物脱氮
