"Datere" asks about:
[A1] I'll give 10 dollars to anybody who washes my car.

[A2] The man who marries my daughter will need to be tough and quick-
thinking.

[A3] This discovery will mean that we spend less on food.

[A4] I will pray that he wins.

[B1] I'll give 10 dollars to anybody who *will wash my car.

[B2] The man who *will marry my daughter will need to be tough and quick-
thinking.

[B3] This discovery will mean that we *will spend less on food.

[B4] I will pray that he *will win.

These must also be considered:

[C1] I *give 10 dollars to anybody who will wash my car.

[C2] The man who *marries my daughter will need to be tough and quick-
thinking.

[C3] This discovery *means that we will spend less on food.

[C4] I *pray that he will win.

For #1, I find A and B acceptable, but not C.
For #2, I find A, B, and C all acceptable.
For #3, I find B and C acceptable, but not A.
For #4, I find A and C acceptable, but not B.

And, for the most part, I have no idea why!