Ex. 4 Open the brackets

By October 1874, Bell's research progressed (to progress) to the extent that he could inform his future father-in-law, Boston Garden Greene Hubbard, about the possibility of a multiple telegraph.
Hubbard instantly saw (to see) the potential for breaking such a monopoly and proceeded (to proceed) with his work on the multiple telegraph but he did not tell (not to tell) Hubbard the he.....