[Grammar] who is visiting Washington next week

[LQZ]

But the officials said he had provided American interrogators with a much more nuanced understanding of the strategy that the Taliban’s supreme leader, Mullah Muhammad Omar, is developing for negotiations with the government of President Hamid Karzai of Afghanistan, who is visiting Washington next week. ---taken from the NYT

Dear teacher,

Could you explain it to me why "is visiting", not "visits"? Thanks a lot in advance.


LQZ

 

[2006]

But the officials said he had provided American interrogators with a much more nuanced understanding of the strategy that the Taliban’s supreme leader, Mullah Muhammad Omar, is developing for negotiations with the government of President Hamid Karzai of Afghanistan, who is visiting Washington next week. ---taken from the NYT

Dear teacher,

Could you explain it to me why "is visiting", not "visits"? Thanks a lot in advance.

One could say 'is visiting', 'is going to visit', 'will visit' or 'visits'.
LQZ

2006