糖尿病患者失明的主要原因是（）。 A.视网膜新生血管产生 B.白内障 C.青光眼 D

烈日：蝉鸣

A．飞雪：梅花
B．秋月：蛇眠
C．春风：稻谷
D．山洪：海啸

（如图）正常眼球的前后径出生时约（）.

A.17mm

B.16mm

C.19mm

D.18mm

E.20mm

The boy was late. He tried to enter the classroom without being noticed by the teacher, but luck ______ him.

A．went with

B．went against

C．went along

D．went over

环境监测功能是如何实现的？

我国各级国家农业技术推广机构应当认真履行《农业技术推广法》的规定的公益性职责，向农业劳动者和农业生产经营组织推广农业技术，实行（）服务。

A.无偿

B.有偿

C.优惠

D.全面