Tìm giúp mình một đoạn văn bản trong các văn bản Làng, Chiếc lược ngà, Lặng lẽ Sapa có ba yếu tố là phương châm hội thoại, nghĩa của từ, biện pháp tu từ

Điền 1 từ thích hợp vào ô trống

Throughout (0) _________ 1990s I worked (1) ______ an accountant in a large furniture factory in London. I had a responsible job and was earning (2) ________ good living. Unfortunately, the company wasn't doing so well, and in 1999 I was (3) _______ redundant. My husband and I (4) _____ always wanted to run (5) _____ own business, and we both felt that now was a good time to (6) ______ a risk and do somthing different. Johnathan, my husband, gave (7) ______ his well-paid but stressful job in the City and we bought a pub in a village near York. It took (8) _____ both quite a long time to (9) ____ used to living in the countryside. Everything happens (10) ____ much slower pace here, but the people are friendlier than in London and we coudn't imagine going back (11) ____ to live. We still work as hard (12) ____ we did before, but it's so much more satisfying working for yourself

Bài 1:

a) Cho a, b, c, d , là các số nguyên thỏa mãn a - b = c + d. Chứng minh rằng a² + b² + c² + d² luôn là tổng của ba số chính phương

b) Cho a, b, c, d là các số nguyên thỏa mãn a + b + c + d = 0. Chứng minh rằng ( ab - cd )( bc - da )( ca - db ) là số chính phương