_____ do you exercise? — Twice a week.[ ]

Things made of plastic are usually _______, but they are _______ to get polluted.

Yang Xiangming, ________teacher of Taizhou Experimental School, devoted his life to saving_______13-year-old boy who fell into water.

Although we’re quite busy with our study , some parents ________give us more pressure .

There’s something wrong ______ Gina and Greg. They haven’t talked to each other for over one month. [ ]