4.Either you or I are average people.＝＞ are 改成 am
5.Many an apple are ripe.＝＞ are 改成 is
6.Maths are my favourite subject.＝＞ are 改成 is
7.There was a terrific accident on the road yesterday.＝＞ terrific改成terrible
8.She spent less days in the city than planned.＝＞spent改成had spent
9.He rose his voice and said,“No!” ＝＞rose 改成 raised
10.May be he knows the truth.＝＞ May be 改成 maybe
11.Everyone of the students,incouding myself,have bought this dictionary.＝＞have 改成 has
12.The president together with several assistants are here.＝＞are 改成is
13.A number of spelling mistakes was found in his article.＝＞was 改成were
14.Fifty dollars seem too much for this coat.＝＞seem 改成seems
15.Romeo and juliet are worth reading.＝＞are 改成is
16.There are an apple and a book on the desk.＝＞are 改成is
17.How John manages to do it were a puzzle.＝＞were 改成 was
18.Two weeks are quite long.＝＞are 改成is
19.The dancer and singer are excellent.＝＞are改成is
20.The dancer and the singer has been praised.＝＞has改成have