临床最常见的前部巩膜炎类型是()
A.结节性前部巩膜炎
B.弥漫性前部巩膜炎
C.坏死性前部巩膜炎
D.穿孔性巩膜软化症
E.以上均不是
参考答案:B
My brother is always making good use of the time _______ he can spare.
A.when
B.in which
C.while
D.that
选育优良自交系有哪些方法,有何异同?