Verified answer

1. us

2. their

3. their

Hope i helped! xx

Our teacher was showing US geography students how to research online. because you are the object of the action (the subject/the doer of the action is our teacher)

Neither the employees nor their manager plan to take THEIR vacation before the deadline. because you are talking about more than one person.

Either the professor or his colleague will make THEIR appearance at the book signing. the same as the second one

;)

Our teacher was showing us geography students how to research online.

Neither the employees nor their manager plan to take their vacation before the deadline.

Either the professor or his colleague will make their appearance at the book signing.

NOTE:: His & Her can only be used when knowing for sure that the noun is masculine or feminine.

Our geography teacher was showing us how to research online.

There was more then one sentence.

We, their, their. You could use "his" for the third if both were male, but their is a perfectly acceptable plural pronoun.

a. her both Shannon and Marge prepared a speech; they did not do one mutually. Shannon became no longer prepared to grant her speech. Marge became no longer prepared to grant her speech. Neither became prepared to grant her speech.

1.us

2.their

3.his

Let me know If i got it right :)