Sure! Let’s break down each question and the reasoning behind the correct answers.

### 1. Investors were caught_____by the sharp drop in share prices
**Answer: A. unawares**

- **Explanation**: The phrase "caught unawares" means that the investors were caught off guard or surprised by the sudden drop in share prices. This is a common expression used to describe situations where someone is unexpectedly faced with something.
- The other options do not fit well in this context:
- **B. unconscious**: This means not awake or aware, which is not applicable here.
- **C. short**: This phrase does not convey the intended meaning in this context.
- **D. red-handed**: This implies being caught in the act of doing something wrong, which does not fit the context of financial losses.

### 2. The government would be forced to use its emergency powers_____further rioting to occur
**Answer: A. should**

- **Explanation**: The use of "should" indicates a conditional situation. It suggests that if further rioting were to occur, then the government would be compelled to act. This matches the context of the sentence which discusses potential future actions of the government related to a possible event (rioting).
- The other options do not fit:
- **B. did**: This is in the past tense and does not suit the future conditional context.
- **C. were**: While "were" might seem plausible, it does not convey the same conditional meaning as "should."
- **D. had**: Similarly, this option does not fit the conditional phrasing required in this sentence.

### 3. Granddad would spend hours talking to us youngsters around the dinner table_____about his happy younger days back east on the farm
**Answer: B. reminiscing**

- **Explanation**: "Reminiscing" means to think back on past experiences fondly or to tell stories about one’s past. This is the most suitable choice because it indicates that Granddad was sharing his happy memories with the youngsters.
- The other options are not quite right:
- **A. recalling**: While this word suggests remembering, it doesn't carry the same connotation of storytelling as "reminiscing."
- **C. reminding**: This suggests that he is trying to prompt others to remember something, which does not fit the context of storytelling.
- **D. memorising**: This means to commit something to memory, which does not apply to sharing stories with others.

### Summary of the Correct Answers
1. A. unawares
2. A. should
3. B. reminiscing

If you have any further questions or need more clarification, feel free to ask!