Past Tense

[Casiopea]

1. "Did you injure him?" <--correct?
2. "You injured him? <--correct?

Both are correct. :D

In 1., the auxiliary "Did" carries Past Tense (Note, Does (present), Did (Past). Within a sentence only one verb can carry tense. That's why "injure" does not have a "-d". That marker is placed on "Did".

You injured him? (Past tense)
Did you injure him? (Past tense)
Did you injured him? (Not OK; there are two Past tense markers)

All the best, :D

[Tdol]

'You injured him?' as a question would often be used to show surprise and check that the information is correct.

[jack]

"That is, the amount of power you get out of the engine compared to the weight of the engine itself is very good." <--correct? why? what does it mean?

"That is, the amount of power you get out of the engine compare to the weight of the engine itself is very good." <--correct? why? what does it mean?

[jack]

"I felt something fell out of my pocket." <--correct? if not, why? what does it mean?
"I felt something fall out of my pocket." <--correct? if not, why? what does it mean?
"I feel something fall out of my pocket." <--correct? if not, why? what does it mean?
"I feel something fell out of my pocket." <--correct? if not, why? what does it mean?

[Tdol]

"I felt something fell out of my pocket." <--correct?
No

"I felt something fall out of my pocket." <--correct?
Yes- it's a bare infinitve (without 'to')

"I feel something fall out of my pocket." <--correct?
Yes

"I feel something fell out of my pocket." <--correct?
No- mismatch of present tense and past when it shoul be any tense + bare infinitive

[jack]

"I felt something fell out of my pocket." <--why is this incorrect?

[Casiopea]

"I felt something fell out of my pocket." <--why is this incorrect?

"I" is the subject of "felt"; "something" is the object of "felt". "fell" carries tense but doesn't have a subject, so its base form is used, "fall":

A. I felt something fall out of my pocket. (Object)
B. Something fell out of my pocket. (Subject)

C. I felt something that fell out of my pocket. (Subject)

By the way, A. and C. carry different meanings.

All the best, :D

[jack]

By the way, A. and C. carry different meanings.

I can't determine what's the difference in meaning between the two. Can you explain it to me? Thanks.

[Casiopea]

By the way, A. and C. carry different meanings.

I can't determine what's the difference in meaning between the two. Can you explain it to me? Thanks.

A. I felt something fall out of my pocket. (Object)
C. I felt something that fell out of my pocket. (Subject)

In A., I noticed the object fall out of my pocket.
In B., I touched the object after it fell out of my pocket. (That is, it fell out, then I picked it up and touched it.)

[jack]

"Your little brother saved you this time." <--correct?
"Your little brother saves you this time." <--correct?
What's the difference in meaning between the two?