---I’ll ask our physics teacher to explain Newton's Second Law of Motion she taught us yesterday．

---That’s just ______ most of the students still have doubt．

1. A.
   what
2. B.
   why
3. C.
   where
4. D.
   how

---I’ll ask our physics teacher to explain Newton’s Second Law of Motion she taught us

    yesterday．

---That’s just _________ most of the students still have doubt．

A．what       B．why          C．where           D．how

--- I ‘ll ask our physics teacher to explain Newton’s Second Law of Motion she taught us yesterday.

----That’s just _______ most of the students haven’t understood.

A. what　　　　

B. why　　　　　

C. how　　　

— I ‘ll ask our physics teacher to explain Newton’s Second Law of Motion, which she taught us yesterday.

— That’s just _______ most of the students haven’t understood.

A. what          B. why           C. how          D. where

.

 — I ‘ll ask our physics teacher to explain Newton’s Second Law of Motion, which she taught us yesterday.

— That’s just _______ most of the students haven’t understood.

A. what          B. why           C. how          D. where