Lovatts Colossus Crosswords $1000 Crossword

I have some questions on here that I cant get and any help would be appreciated. Across: #75. Conceal?7? T_CRE_E. #272. Anxious?7? U_T_G_S. #277. Decides on, ... for?3? _TS. Down: #134. Safer (Bet) ?5? S_E_R. #151. Tar substance?7? TIT_MEM. #266. Mawkish?5? S__PY. #268. Plumped for?5? C_ORE. #280. Humdrum?7? TOD_O_S. #291. Satellite Spying, ... Reconnaissance?6? SE_IAL.