If Rita opens /will open a boutique in the High Street, she’ll make lots of money. If the economy doesn’t...

1. If Rita opens a boutique in the High Street, she’ll make lots of money. The correct form to use here is "opens," because this sentence is a First Conditional structure. It deals with a real and possible condition (Rita opening a boutique) and its probable future result (making lots of money).

2. If the economy doesn’t improve, lots of businesses will close down. The right choice is "will close down," because this is another instance of the First Conditional. It expresses a future possibility that is realistic if the condition (the economy not improving) is met.

3. This burglar alarm is so sensitive: it goes off if a mouse runs across the floor. "Runs" is the correct form to use here. This sentence describes a general truth or habitual action – the alarm always goes off when a mouse runs across the floor.

4. George may go to prison unless he pays his taxes. "Pays" is appropriate in this case. This sentence structure is a First Conditional in a negative form (using "unless"), which means it requires the present simple "pays" to talk about a likely future event based on the current action of paying taxes.

5. The company would be more successful if it spent more money on advertising. "Would be" and "spent" are correct here, forming a Second Conditional sentence. This conditional type is used to discuss hypothetical situations and their probable impacts, in this case, the success of a company under different circumstances.

6. If the employees of a company are happy, they work harder. "Are" and "work" fit correctly in this sentence, which expresses a general truth - a situation where the condition always leads to the result.

7. We might sell our business if it makes another loss this year. "Makes" is the appropriate form to use. This is an example of a First Conditional, expressing a real possibility in the future (selling the business) contingent upon a specific condition (making another loss).

8. It looks like Molly’ll be okay, unless something new happens. "Happens" is the correct choice, applying once again the First Conditional structure in a negative form with "unless." It discusses a real possibility that could alter the current expectation (Molly being okay).

9. Unless Shelly had read him wrong, Jack would have found her unorthodox approach irresistible. "Would have found" correctly completes this sentence. This is a Third Conditional sentence expressing a hypothetical situation in the past and its possible past result, contingent on whether Shelly’s reading of the situation was correct.

10. Mat would not trust that unless he had to. "Had to" is the correct form. This sentence structure implies a condition under which Mat would be forced to trust, which is hypothetical and discussed as a less likely scenario.

If Rita opens a boutique in the High Street, she will make lots of money. This sentence is in the first conditional, which is used to talk about possible future events and their likely results. It suggests that if Rita takes the action of opening a boutique, the result will be that she will make lots of money.

If the economy doesn’t improve, lots of businesses will close down. This sentence is in the second conditional, which is used to talk about hypothetical or unlikely future events and their possible outcomes. It suggests that if the economy does not improve, the likely result will be that lots of businesses will close down.

This burglar alarm is so sensitive: it goes off if a mouse runs across the floor. This sentence is in the zero conditional, which is used to talk about general truths or facts. It suggests that the burglar alarm always goes off when a mouse runs across the floor, indicating a cause and effect relationship.

George may go to prison unless he pays his taxes. This sentence is in the first conditional, suggesting that if George does not pay his taxes, there is a possibility that he may go to prison.

The company would be more successful if it spent more money on advertising. This sentence is in the second conditional, suggesting that if the company spent more money on advertising, it is likely that it would be more successful.

If the employees of a company are happy, they work harder. This sentence is in the zero conditional, suggesting that when the employees of a company are happy, the result is that they work harder.

We might sell our business if it makes another loss this year. This sentence is in the first conditional, suggesting that if the business makes another loss this year, there is a possibility that the owners might sell it.

It looks like Molly’ll be okay, unless something new happens. This sentence is in the first conditional, suggesting that if nothing new happens, it is likely that Molly will be okay.

Unless Shelly had read him wrong, Jack would have found her unorthodox approach irresistible. This sentence is in the third conditional, which is used to talk about hypothetical events in the past and their possible outcomes. It suggests that if Shelly had not read Jack wrong, the result would have been that he found her approach irresistible.

Mat would not trust that unless he had to. This sentence is in the second conditional, suggesting that if Mat did not have to, he would not trust the situation.