We are speaking, however, of two possibilities of the past difficult to trace in the present.
The inner marginal haemal duct, however, underwent considerable changes, although the precise timing of these events is difficult to trace based on the present data alone.
However, interviewing postpartum women outside the health facility is problematic in the Tanzanian setting, since it is difficult to trace women at their home addresses once they leave the hospital, and transportation to rural areas can be difficult.
From the present state of plastids, however, it is difficult to trace the evolutionary steps involved in this momentous development, because all modern-day plastids have fully integrated into their hosts.
Since most deaths in Ethiopia occur at home [ 25], it was difficult to trace all deaths.
It will be more difficult to trace these people and it already is difficult," says David Mussington, senior scientist, at RAND, in Arlington, Virginia.
Senator John McCain's family tree proved more difficult to trace.
The stalking, which continues sporadically today, is at once bizarre, terrifying and, owing to Paul's deep pockets, maddeningly relentless and difficult to trace, according to the book.
The Hanks genealogy is difficult to trace, but Nancy appears to have been of illegitimate birth.
No patients were known to have been sickened, although such cases would be difficult to trace.
