单项选择题
A.is B.are of C.is of D.are
Can we change the location for the tung-oil（）that for t...
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
Calcium carbide and acetone are counteractive（）nature.A...
单项选择题Calcium carbide and acetone are counteractive（）nature.
A.by B.in C.from D.with
At sea，on what occasion would you display two red light...
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?（）.
A.When vessel is on fire B.When vessel is not under command C.When vessel is carrying the dangerous cargoes D.When vessel is restricted in her ability to maneuver
