The Georgetown and George Washington basketball teams are at an early-season crossroads in home games tonight against teams that qualified for the NCAA tournament last season.

At Georgetown (WTTG-TV-9, 8 p.m.), St. Bonaventure, minus stars Greg Sanders and Glenn Hagen but with everybody else back, tries to stop the Hoyas' 16-game McDonough gym wining streak. The question for Georgetown is: Will the Hoyas suffer a letdown after beating Maryland?

At George Washington, Villanova, NCAA quarterfinalist a year ago, plays the Colonials in an 8 o'clock matchup of two of the Eastern Eight's supposed top three teams. The question for GW is: Will the Colonials straighten out a shaky start, as they did last season?

Elsewhere, Maryland begins a threegame road trip at the Air Force Academy (WDVM-TV-9, 8 p.m.); American U. debuts at its Fort Myer home court against Trenton State at 8; Howard hosts Shaw at 8; Catholic travels to St. Francis (Pa.) at 8 and Virginia hosts Old Dominion at 7:30.

Georgetown's victory over Maryland was its first since 1970, and Coach John Thompson has tried to impress upon his players, who executed exceptionally well in that game, that they should not interpret the victory as "making their season."

"I think they understand that," Thompson said. "But I just want to make sure."

So, the day after the Maryland game, Thompson held what he expects to be his toughest practice of the season.

Despite his 28 points against Maryland, freshman guard Eric (Sleepy) Floyd will continue to come off the bench, unless 6-foot-11 Tom Scates' sprained ankle keeps him out, so 6-foot-9 freshman Ed Spriggs can get experience and so the Hoyas have a sixth man who can score. Thompson also is looking to develop depth, since only the four returning starters have any experience to speak of.

It is likely that, until that backup strength materializes, the Hoyas will continue to play a slower tempo than they did last season. St. Bonaventure Coach Jimmy Satalin, however, would like a faster paced game tonight.

The Bonnies, 21-8 last year and 70-point victors over Steubenville in Wednesday's opener, play a different style of basketball without Sanders and Hagen. The Bonnies used to clear out a side of the court for one of them.

"Whenever somebody else scored last season it was cheap stuff or something that just happened," Satalin said.

Now the Bonnies are moving more and screening offensively. Although Steubenville never will be mistaken for Ohio State, the Bonnies made 15 straight shots at one stage against the Barons; only six of them were layups.

George Washington, blasted by its coach for a lack of effort in the Virginia Tipoff Tournament, is the type of team that plays very well when it is emotional and confident. The Colonials, however, can beat few teams on talent alone.

The circumstances this season are similar to those early last year. That's why Coach Bob Tallent considers the Eastern Eight opener so vital. A year ago, the Colonials opened with victories against two relative patsies, then blew a 16-point lead with 10 minutes remaining against Massachusetts.

In the next game, GW was 17 points down at halftime to a highly touted Wisconsin team. The Colonials came back to win that game, then beat Maryland in their next outing. Tallent thinks a victory over Villanova will establish that sort of confidence again.

Despite losing Keith Herron and Whitey Rigsby, Villanova is solid again, with guards Rory Sparrow and Steve Lincoln (out of Eastern High) and center Alex Bradley. The Wildcats' only collegiate game has been a breeze over Merrimack, but they beat the Puerto Rican national team twice last week on the road. They will press full out tonight in all probability.

A three-game road trip outside the Atlantic Coast Conference is a rarity for Maryland. Coach Lefty Driesell has not played three straight away games outside the conference since 1972-73.

Such scheduling is a sign that he expects good things from this team, three of whose top seven players are freshmen and three are sophomores. The Terps showed flashes of brillance against Georgetown, but faltered at the end with poor shot selection in the 68-65 defeat.

After tonight's game, which the Terps should win fairly easily, they face a good test at Nevada-Las Vegas Monday night and play a mediocre Penn State team at Hershey Thursday night.