A.I'm not satisfied with your explanation of where you <u>were</u> last night.
b.I came into the room when Mary <u>was playing</u> the piano.
c.no error!!!
d.There <u>are</u> some sheep in the field.
e.Playing the drums and singing<u> is </u>difficult.
After two days of hiking, we reached the apex of the mountain.
Feudalism helped protect communities from the violence and warfare that broke out after the fall of Rome and the collapse of strong central government in Western Europe. Feudalism secured Western Europe's society and kept out powerful invaders. Feudalism helped restore trade. Lords repaired bridges and roads.
