помагите решить номер 2 срочно

A teacher explained tot the pupils that the earth ... round.
a)is
b)were
c)-----
d)would be

1)the bolshoi theatre ... in moscow.
2)the capital of russia ... st petersburg.
3)the kremlin ... in red square.
4)pushkin and pasternak ... russian writers.
5)the neva and the lena ... meseums.
6)the tretyakov gallery and the russian museum ... thettres.

while, nowadays, use, both, foreign, You dont say(so)!, smell pleasant, to climb(climbed), blossom, mild, climate, possible, impossible, to breathe (breathed), to protect (protected), harm, to do a lot of harm

надо!