用适当的关系词填写下面文章中的句子并体会它们的共同特征 1．The time ______________ I first met Nelson Mandela was a very difficult period of my life. 2．It was in 1952 and Mandela was the black lawyer to ______________ I went for advice. 3．He was generous with his time，for _______________I was grateful. 4．The school _______________ I studied for only two years was three kilometres away. 5．However，this was a time ______________ one had got to have a passbook to live in Johannesburg.

when　

whom　

which　

where　

when