1: They were picking up litter on the beach then

2 :

1: During the floor, you should listen to instructions of local authorities

2: Mars is one of the most promising of planets life in solar system

question 1 : How often earthquakes occured in this region?

question 2 : I can found a wide range of beauty products in our store

question 2: People still send the letters for each other in 2050

question 1: I think robots can't be replace the role of teachers education

BaO, CO2, NO, P2O5

biến đổi vật lý

5P + O2 = P2O5

P2O5 + 3H2O = 2H3PO4 + H2

H3PO4 + 3NaOH = Na3PO4 + 3H2O

2NA3PO4 + 3Ca(OH)2 = Ca3(PO4)2 + 6NaOH