31, was -> was walking ( QKD)
32, eaten -> had eaten ( QKHT )
33, did you do -> was you doing ( QKTD )
34, has already -> had ( QKHT )
35, during -> since
36,has disappeared -> disappeared ( QKD )
37, was cooking -> cooked ( QKHT )
38,saw -> have seen ( HTHT )
39, graduates -> had graduated ( QKHT )
40, had been -> has been ( HTHT)