Điền từ thích hợp vào chỗ chấm

The first groups of people to discover New Zealand came from Polynesia. Exactly when these explorers arrived has often been a (1).................................. for debate, but today the general understanding is that it was during the 13th century (2).................................. their canoes eventually landed on New Zealand's shores. In some ways the new country must have seemed (3)............................... an ideal place to settle: the land was fertile, and thick forests provided fire wood, shelter, and building materials. Still, life would have been challenging for the different Polynesian tribes, who had to (4)................................. to a new environment. The tribes only began to refer to themselves as Maori, (5).............................. "ordinary people", when Europeans in (6)................................. of new opportunities began arriving in the 18th century. To the Maori, of course, the European settlers and sailors were not "ordinary" (7)............................................ very strange.It was not only the knowledge of canoe-building and navigation that the Polynesians brought to New Zealand. They were also skilled craftsmen. There is archaeological evidence that the tools they produced were (8).................................... high quality and would have enabled tribes to plant and harvest crops. Craftsmen were also occupied with making weapons such as knives and some crafts that had once been popular in Polynesian islands were no (9)...................................done in New Zealand although researchers are unsure why. Pottery is an (10)..............................  of this despite the fact that the clay needed to make pots and bowls could easily be found in the new country.