Which is the correct usage of the words does/do/did?

Question

1. What did/do the wolf think fell on him?
2. what did/does the thief think he fell on?
3. The do/did not know what they're afraid of?
4. The thief does/did not know what an eek is.
5.The house in the story has/had a thatch roof.

Is it safe to assume that one can tell which word to use by looking at other verbs in the sentence?

Answer 1

In one: did would work but not do
two: is correct both ways although the "does" would be uncommon and a little awkward.
three: (i assume you meant they) either is correct
four: both are correct
five: both would work

It all depends whether you would like to say things in the past or present tense. In a lot of sentences you can't use the other verbs in the sentence for the correct tense or form. An example of this is number four. Know is the present form of the verb "to know" yet by adding did, it converts the sentence to the past.
The only reason that both do not work in number one is because do is being used in the third person, and do is a verb only for the first and second person.

Hope that helped!!

Answer 2

what did the wolf....?
what does the thief...?
he did not know....?
the theif does not know..
the house in the story has a thatch roof.

think of the context of the sentence. is it present tense or past tense? then choose.

Answer 3

1. did
2. does
3. do ( you forgot the "y" or they)
4. does
5.has

Answer 4

this words are verb... "does" is a present tense, "do" is the past tense, and "did" is the ast participle of the verb...

Answer 5

1 did
2.did
3.do
4.does
5 has or had