(S (S (BASENP (DT The) (NNS archaeologists)) (VP (VBP fear) (SBAR (S (BASENP (PRP they)) (VP (MD may) (VP (VB have) (S (VP (TO to) (VP (VP (VB postpone) (NP (BASENP (NN work)) (PP (IN for) (BASENP (NN security) (NNS reasons))))) (PP (IN over) (BASENP (DT the) (NN summer) (NNS months)))))))))))) (PERIOD .))