By the mid-1950s , numerous dams had been constructed on the main flow of the Ōi River , and developers began to turn their attention to its various tributary streams .
ADP DET NOUN , ADJ NOUN AUX AUX VERB ADP DET ADJ NOUN ADP DET PROPN PROPN , CCONJ NOUN VERB PART VERB PRON NOUN ADP PRON ADJ NOUN NOUN .