As Congress races the clock to get home for electioneering, it appears it won't meet its targeted adjournment date of this Friday. The session is now expected to end early Sunday morning with a last-minute flurry of legislation. The principal item of unfinished business: passage of 13 appropriation bills. At midweek, final action seems likely on only six or seven of the measures. The rest -- stalled by disputes ranging from International Monetary Fund funding to use of sampling in conducting the 2000 census -- probably will be incorporated into a Continuing Resolution to avert a government shutdown, for which neither Republicans nor Democrats have an appetite. One high-profile piece of legislation not expected to make it into law is the $80 billion tax-cut package passed by the House last week, which includes a reduction in the estate tax sought by small business. Congressional observers predict, though, that the Continuing Resolution will include a reauthorization of the expiring R&D tax credit, an industry priority.