SAT grammar questions..please help!!

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1
  1. With the current difficulty in A(filling) seats on juries, B(some) argue that jurors should be compenstaed C(for lost wages), particularly given the D(increasing) length of trials. E(No error).

I was wondering why A is not wrong. I thought it should be ‘filling up seats on juries’? Or ‘filling’ also works? Can someone explain this to me please?

  1. The number of people who call themselves storm chasers (has swelled, some of them have even turned )their hobby into a business by taking people on expeditions to view tornados. A. has swelled, some of them have even turned B. has swelled, and some have even turned C. swelled, and some even turning D. have swelled, some of them have even turned E. have swelled, some of whom even turned

My question is-why is E wrong? It seems perfectly fine to me…

2
  1. *fill* and *fill up* are both correct. The latter is useful when you are dealing with quantities or amounts and want to communicate that the item to be filled (like a cup or gas tank) is *completely* full. To fill a seat with a person simply means that it is occupied. To fill up a seat means that the cushion is completely covered.
  2. E is incorrect for 2 reasons. First, "number" in this case is a singular noun and requires a singular verb. Second, the relative pronoun phrase "some of whom" must immediately follow the noun phrase to which it refers; in E, it would follow a verb phrase ("have swelled").
3

Oh dear. I should have clarified that “fill” and “fill” up both both idiomatic, but only “fill” is appropriate in the context of filling jury seats with juries.