Trong hiện tượng giao thoa sóng nước với hai nguồn kết hợp S1 và S2 dao động theo phương thẳng đứng, cùng pha, cùng biên độ a, sóng do hai nguồn tạo ra có bước sóng 3 cm. Phần tử M ở mặt nước cách S1, S2 lần lượt là 3 cm và 9 cm có biên độ là

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Supply the correct verb form or tense 1, Hello, my name (be) ________ Hoan and this is my family. We (live) __________ in a big city in the South of Vietnam. There (be) ________ four people in my family: my father, my mother, my sister and I. My father (work) __________ in a factory. My mother (teach) _________ English in a secondary school. My sister (study) __________ at the University of Economy. I (go) ____________ to a secondary school. We usually (have) ___________ lunch and dinner at hame. On Sunday evening we sometimes (go) ____________ out for dinner. My sister (like) ______ music. She often (go) _________ to the concert at the weekend. My father (watch) ____________ TV every night and my mother (do) __________, too. 2, Lan (not have) _____________ many friends in her new school. 3, Hung (come) ____________ from Vinh but he (stay) _____________ with his relatives in Ho Chi Minh at the moment. 4, We (not drive) _____________ to work every day. We (go) ________ by bus. 5, Who you (talk) ____________ to on the phone now, Minh? 6, Where your new friend (live) ___________ Nga? She (live) _________ on Hang Bac street. 7, You (be) in class 7A? No, I (be) ____________ in class 7D 8, It's a lovely day. The Sun (shine) __________ and the birds (sing) _____________. 9, What the usually (do) ____________ in the evening? She usually (play) _________ cards or (watch) ______________ TV. 10, They (have) ___________ a party toningt. They (have) __________ sandwiches and (drink) __________ champagne.