Jawaban:

1. They have checked the plane schedule.(+)  

  They have not checked the plane schedule.(-)

   Have they checked the plane schdule? (?)

2. We have learned about Present Perfect Tense. (+)

    We have not learned about Present Perfect Tense. (-)

    Have we learned about Present Perfect Tense. (?)

3. Anton has come here (+)  

   Anton has not come here. (-)

   Has Anton come here. (?)

4. Sasa and Tata have changed their costume. (+)

   Sasa and Tata have not changed their costume. (-)

   Have Sasa and Tata changed their costume. (?)

5. He has  fixed his computer. (+)

   He has not fixed his computer. (-)

   Has he fixed his computer? (?)

Penjelasan:

sewaktu membuat kalimat negatif dalam bahasa inggris tobe harus disertai dengan not contoh : am not, was not, have not, has not, were not ,are not rumusnya untuk kalimat negatif adalah subjek + tobe + not + kata keterangan sedangkan untuk kalimat bertanya tobe berada didepan kalimat baru disertai subjek dan keterangan rumusnya : tobe +subjek + kata keterangan.

semoga membantu dan benar

semangat kawan .... terima kasih