onthevisitto...是个介词短语,意思是“去.参观”或“在去.参观途中”
动词词组常用payavisitto...
例如:
Lastweekwewent on a visit to TokyoDisneyland.
WeareleavingonSunday to go on a visit to Yan'an.
Iamgoing to pay a visit to Shanghai.
Didyou pay a visit to theleaningtowerinPisawhileyouwereinItaly?