有几题英语题请帮忙解答,并讲解一下,谢谢!

有几题英语题请帮忙解答,并讲解一下,谢谢!
1.It's seven o'clock in the evening.Daniel with his parents _______TV.
a.watchb.watchs c.is watching d.are watching
2.When did your father ______youe mother?
a.marry b.marry to c.marry with d.get married
3.There ______great changes in our country during the past twenty years.
a.have beenb.has beenc.has hadd.have had
4.Mary is flying to France soon.She will arrive ______ Paris ______the morning of July9.(此题关于地名和时间怎样用介词,能说一说吗?
a.at;in b.in;on c.in;ind.at;on
第四题谢谢,讲的非常清楚.第一题为什么是is watching ，而不是are watching,能再说一下吗？