前，地面气象观测的目测项目包括（）。
A.固态降水
B.云
C.日照
D.能见度
E.电线积冰
F.天气现象
参考答案：B, D, F
— ____ have you been at this factory?
— I've been here since 1993. [ ]
A. When
B. How long
C. What time
D. How often
