điền từ Who  Which  that how  often  whose vào chỗ chấm
1 Look at this photo . My sister is the person .................. is smiling
2. ......................... is your coat ? It 's the one with the red buttons
3. The saxophone in an instrument ................... is difficult to play 
4 That 's the boy  ..................uncle won the gold medal for swimming  
5. .................................. do you go to the cinema? I go once a month