原尿生成的部位是
A．肾小球B．近球小体C．近球小管D．髓袢E．远曲小管和集合管
参考答案：A
导致成年人牙劈裂而丧失的主要疾病是()
A．深龋
B．畸形中央尖
C．遗传性乳光牙本质
D．楔状缺损
E．牙隐裂
It'll stop the sand from moving _____ the rich farm land in the south. [ ]
A. to
B. towards
C. at
D. into
