Translation:The courier carries, but does not build a building.
This is bad English. "To carry" is a transitive verb, and requires a direct object. The implication of this sentence is that the courier carries a building, which is absurd. Better English would be, "The courier carries things, but he does not build a building"; still better, "but buildings he does not build."
Yup. That's why I opened this page too. It's the second time in this course that they use a transitive verb intransitively. Carry is very rarely intransitive. The only example I can think of is "voices carry well in this auditorium." They need to correct this and say "the courier carries __ (things, letters, or packages)."
P.S. @contributors: there was no option for reporting the English sentence so I checked all three of the available options. That's my way of saying the real reason for the report is not displayed. :)