Use of English · Part 5
Rubber is the name of an elastic (0) MATERIAL which can both stretch and (1) ........... It can be either (2) .......... from natural sources, or made in factories. Natural rubber (3) .......... from the white sap of some trees. To collect this sap, people have to cut the tree in a special way for the sap to slowly…
Desbloqueja tots els exàmens, simulacions il·limitades, les 80 fases del joc i molt més.