it may someday be worthwhile to try to recover uranium from seawater , but at present, this process is prohibitively expensive

a. it may someday be worthwhile to try to recover uranium from seawater
b. Trying to recover uranium out of sea water may someday be worthwhile
c. To try for the recovery of uranium out of sea water may someday be worthwhile
d. Recovering uranium from seawater may be worthwhile to try to do someday