Sentence A: What concern me are the election results
Sentence B: The time when the apartment building in downtown Milwaukee started on fire has been determined by the fire department, but what is more problematic to establish is the source of the flame, the mechanism by which it ignited the building, and the extent of the damage
Sentence C: Around the corner, there are a bakery and a supermarket.
The above sentences are correct. I, however, marked the option which says what is more problematic to establish are the source of the flame, the mechanism by which it ignited.. considering that it were a list - the source of the flame, the mechanism by which it ignited the building, and the extent of the damage and hence plural as in sentence C.
1) Where did i go wrong?
2) When do we use 'is' and when do we use 'are'? Please explain with some more examples.
Sentence B: The time when the apartment building in downtown Milwaukee started on fire has been determined by the fire department, but what is more problematic to establish is the source of the flame, the mechanism by which it ignited the building, and the extent of the damage
Sentence C: Around the corner, there are a bakery and a supermarket.
The above sentences are correct. I, however, marked the option which says what is more problematic to establish are the source of the flame, the mechanism by which it ignited.. considering that it were a list - the source of the flame, the mechanism by which it ignited the building, and the extent of the damage and hence plural as in sentence C.
1) Where did i go wrong?
2) When do we use 'is' and when do we use 'are'? Please explain with some more examples.
