Add time to current-row by previous column in an excel column?

I am trying to add 20 minutes to the time in the previous column on the same row, using Excel 2003. Is this possible? I'm having trouble figuring out how to get the current row. I can just use D to identify the column.

Things I've tried include [], and $. I'm not sure what I should be searching for, so terminology would also be useful.

In summary, basically: how to reference the current row in Excel, like D$current_row.

Example:

D       E
12:00   12:20
12:20   12:40
02:00   02:20
...     ...+20

Answer

In column E type in this formula:

=D1+TIME(0,20,0)

Then click and drag the bottom right corner of the cell to copy the formula down column E to as far as you need.

I've used "D1" assuming your data is on the first row. If this is not the cause, just change the number to whatever row the data starts on.

E.g. assuming data starts on row 20:

=D20+Time(0,20,0)