单项选择题
Can we change the location for the tung-oil（）that for the gum rosin?
A.by B.for C.into D.with
单项选择题 Calcium carbide and acetone are counteractive（）nature.
单项选择题 At sea，on what occasion would you display two red lights at night or two black balls during the day?（）.
单项选择题 Argon is classified as a（）.
