单项选择题
Day-shapes must be displayed（）.
A.between sunset and sunrise B.only between 8 AM and 4 PM C.during daylight hours in any visibility D.during daylight hours in unrestricted visibility only
单项选择题 Daylight savings time is a form of zone time that adopts the time（）.
单项选择题 Dacron sails，when not in use，may be damaged if（）.
单项选择题 Cyclones that have warm sectors usually move（）.
