IX.
1.use->using(What about+V-ing)
2.have->has(water:UN)
3.because->because of(because of+N/V-ing)
4.will be->are(if 1)
5.amazing->amazed(adj-ing:vật,adj-ed:người)
6.polluted->pollution(land pollution:ô nhiễm đất)
7.will->won't
8.go->going(How about+V-ing)
9.although->because
10.believes->believed(report speech)
11.have stayed->stayed(last summer->QKD)
12.that->it
