My uncle, who is a businessman, often travels _____ air.
- A. on
- B. in
- C. by
- D. from
Explanation
The fixed expression is “travel by air,” where by identifies the means of transport. “On air” and “in air” do not fit this expression.
Explanation
The fixed expression is “travel by air,” where by identifies the means of transport. “On air” and “in air” do not fit this expression.