Curiouser and curiouser. . .

As our son nears his fourth birthday we have noticed his vocabulary and consequently his conversation level reaching a new high. The ''whys?'' and the ''how comes?'' are starting to demand logical answers and detailed explanations. ''I don't know'' and ''That's just the way it happened,'' aren't ending conversations the way they used to.

It was 7 a.m. and we had just finished talking long distance to Nanny in California.

''Mom?''

''Yes.''

''Mom, how did Nanny get in the phone?''

''She didn't, sweetie, that is just her voice.''

''How did her voice get out of herself?''

''Well, gee.'' It was just too early in the morning for this drill. ''How about some breakfast?''

''Mom!'' (He is wise to that change-the-subject trick.) ''How does Nanny's noise get here?''

''It came through those wires out there.'' I took him to the window. ''See those telephone wires?''

''Nanny's in there?''

''No. But those wires go to Nanny's house and she talks into them, and it comes out here.''

''Oh. Does Dad know that?''

''I doubt it,'' I said smugly.

''Mom?''

''Yes?'' I set a bowl of Cheerios in front of him, and he studied them thoughtfully.

''Mom, how do Cheerios get holes in them?''

''Oh, there's a machine that does it.''

''How?''

''Golly, Ben, I don't know how it works.''

''Why don't you know?''

''Nobody ever told me.''

''Does Dad know?''

''I doubt it.''

''Who knows?'' he pursued.

''Nobody I know.''

''But I know. And you know me.''

''You know?'' (Who told him!)

''Yup.'' And without even bothering to share his secret he shoveled in another spoonful of cheer . . . and the wheels kept turning.

''Why is milk white, Mom?''

''I don't know.'' It was 7:15. I was still half asleep but bright enough to know I was being humbled by a bowl of cereal.

''Guess,'' he said.

''I guess that's just the way God wanted it.''

''He didn't make milk green!''

''No, He didn't,'' I said positively, my confidence building.

''God made the trees green, right?''

''Right.'' (I like rhetorical questions.)

''And the grass.'' He paused and took a drink of orange juice. ''Why didn't God make our grass green?''

''Oh, Mommie and Daddy just didn't water it enough.'' (He's not going to leave it at that, I know!)

''Is our grass rusty?''

''It's thirsty.''

''Water makes things rusty.'' He said with conviction.

''Yes, it does. Metal things.''

''Does Dad know that?''

''He might.''

He continued scooping spoonfuls of milk into his mouth and when he had almost finished, the treasure at the bottom of his bowl provoked him into a new vein of questioning.

''How come sugar is sweet?''

''Oh, let's see.'' (Surely I can come up with an answer for that.) ''I think sugar is sweet because - that's what tastes good on cereal!'' (The more I hear myself talk the more I wonder why I bother.)

''But Mom, WHY is it sweet?''

''I don't know. Here comes Dad, ask him.''

''Dad, why is sugar sweet?''

With no hesitation he began, ''Well, because it wouldn't taste very good if it was sour.''

''Oh, brother,'' I mumbled into the toaster.

''But Dad, WHY?''

''Well, it's just a natural phenomenon.''

''What's that, Dad?''

''That's like a miracle.''

''Dad, why is the smoke alarm yelling?''

''Well, because Mom is burning the toast.''

''But why does she do that, Dad?'' Ben cocked his head, looking like a curious puppy.

''Nobody knows. But she's good at it, don't you think?'' my husband replied with a giant grin.

''Mom? Why does toast get black when you burn it up?''

''Ben,'' I mimicked his tone, ''WHY are you driving me crazy with all these questions?''

''Mom,'' he gave me the most patronizing look, ''I guess that's just the way God wanted me.''