填空题

Questions 47 to 51 are based on the following passage.
You ask about my name, Olafur Egilsson: Olafur is my given name, Egilsson my surname. People familiar with Icelandic culture can tell at a glance that my father’s given name is Egil—that I am "Egil’s son". Icelanders maintain the old tradition of adding "son" or "dottir"(daughter) to the father’s given name to form surnames. Hence every generation in a family has a new surname. With the trend towards equality between the sexes in every field, Icelandic law now also permits you to take your mother’s given name as the basis for your surname.
As clever readers will surmise, what’s my daughter’s surname Of course not everyone is aware of our traditions. One day I received a letter from the school in France where my daughter was studying. It was addressed to me as "Mr. Olafsdottir’!
At the mention of "Iceland", the picture that pops into your head is probably one of snow and ice. Actually, in summer Iceland is full of flowers and singing birds. Even in winter, thanks to the tempering influence of the Gulf Stream, the country is not really very cold. For instance, the average temperature in Reykjavik, the capital, is — 0.5℃ in January—brisk, to be sure, but hardly Arctic. Compared with Beijing in January, with its average temperature of — 10℃, Reykjavik is almost balmy. Names can be misleading. Greenland, deceptively, has vastly more ice than Iceland does, and Iceland is vastly more greenery.
It may surprise you to learn that Icelanders enjoy swimming in open-air pools during the winter. Young and old, we all swim outdoors in cold weather. Superior hardiness No, it’s thanks rather to Iceland’s abundant geothermal resources.
Running southwest to northeast across our island nation is an active volcanic zone that provides plenty of renewable non-polluting geothermal energy. Geothermal water provides heat for 86 percent of the country’s people and makes Reykjavik (which in Icelandic means "bay of smoke") paradoxically a "no smoke city".
What’s the surname of writer’s daughter