B) at four o'clock
когда время какое-то обозначается, в которое начали делать действие, то всегда 'at'
[t] thanked, looked, worked, walked, finished, discussed [d] opened, closed, lived, studied, learned, returned, stayed, continued, received, answered, copied [id] translated, repeated
sing - singer (певец)
help - helper (помощник)
count - counter (счетчик)
danse - danser (танцор)
I take a walk with my girlfriend but she brought a puppy and did not want to play with me
1 impressive
2 natural
3 scientists
4 volcanic
5 strangely
6 explanation
7 amazing
8 survival
9 a greedy businessman (OR) greedy businessmen
if it is singular, it needs 'a'
10 protection