11/ have not made( vì có "yet" nên dùng hiện tại hoàn thành)

12/ have ever seen

13/have never eaten

14/were learning( giờ này ngày hôm qua nên dùng thì quá khứ tiếp diễn)

15/ is going to visit( be going to)

$\text{10. was cooking }$

$\rightarrow$ QKTD 

$\rightarrow$ S + was/ were + Ving 

$\text{11. have not made }$

$\rightarrow$ HTHT - S số nhiều - have - V3 

$\rightarrow$ S + have / has +V3 

$\text{12. have ever seen }$

$\rightarrow$ HTHT - ever - S số nhiều 

$\rightarrow$ S + have / has + V3 

$\text{13. have never eaten }$

$\rightarrow$ HTHT - never - S số nhiều - V3 

$\text{14. were learning }$

$\rightarrow$ QKTD - at this time yesterday 

$\rightarrow$ S + was/ were + Ving 

$\text{15. is going to visit }$

$\rightarrow$ TLD - next week 

$\rightarrow$ S + be + going + to + V