1. had never been, read
2. Have you decided
3. I have just had
4. did, haven't written
5. bought
6. left
7. Has the plane landed? landed
8. hasn't rained
9. Have you seen? It has run away
10. met, haven't seen
11. saw, didn't buy
12. fell, hasn't ridden
13. died, have never visited
14. went, has come
15. Have you spoken? had
16. Have you ever been? went
17. Have you seen? haven't seen
2/7-1/6+1/9=(36-21+14)/126=29/126
1-Finding,
2-centuries
3-answer
4-matter
5-centuries
6-laughed
Насколько я понял, то тут просто во всех пропусках написать "the" (без кавычек).