— __________ do you go to work?
— I go to work by bike. [ ]
A. Where
B. Who
C. How
答案:C
用石墨炉原子吸收光谱法测得尿铅浓度为100μg/L,同时,用比色法测得尿中肌酐浓度为2.0μg/L。用肌酐校正的尿铅浓度是()
A.30μg/g
B.40μg/g
C.50μg/g
D.60μg/g
E.70μg/g
爆破材料库附近()m范围内严禁爆破。
A、20
B、30
C、40
D、50