I'm not sure the best way to ask the question, but I need a formula that will
do the following:

Sheet 1 has all the information, for example:
A B C D
1 Date Activity Cost IsDeductible
2 1-10 Purchase $12
3 1-10 Donation $5 x
4 1-12 Purchase $2
5 1-13 Purchase $25 x


I want Sheet 3 to only show the rows that are marked 'x' in the column
'IsDeductible' (column D):
A B C
1 Date Activity Cost
2 1-10 Donation $5
3 1-13 Purchase $25

Thus far I've only been able to create formulas that will carry over the
information from Sheet 1 into the corresponding row of Sheet 3, meaning there
is a gap (which may mean a gap of 100 of cells or more--won't work):
A B C
1 Date Activity Cost
2
3 1-10 Donation $5
4
5 1-13 Purchase $25

Sorry if there is TMI. I've searched for similar questions, but haven't
found any applicable answers. Maybe there is a simple operator I am unaware
of?
Any suggestions would be appreciated.