Revise the following sentences, correcting any errors.
i. Neither the boys nor he knows the one I referred to.
ii. There are a large number of birds on that tree.
iii. Each of the horses rear and threw their riders.
iv. I am very surprised at his succeeding.
v. He expected to have failed in that subject.
vi. It is I who is responsible for the cessation of fire.
vii. Alarmed at the news, the boat was launched at once.
viii. We guarantee to fully satisfy all your needs.