**Rule:** The Simple Present Tense is the standard tense for future events that are part of a fixed schedule or timetable. The start time of a concert is a scheduled event. Both (b) and (d) are common for scheduled events, but the simple present is often preferred for official times.

**Rule:** The Simple Present Tense is used for future events that are part of a fixed public timetable, such as transport schedules. Option (a) is for personal arrangements. Option (b) is a prediction. Option (c) is future perfect, which doesn't fit the meaning.

**Rule:** The Future Perfect Tense (will have + past participle) is used to describe an action that will be completed by a certain time in the future. The action of 'saving enough money' will be finished by the deadline, 'the end of the year'. Option (d) would imply the saving is still in progress.

**Rule:** The 'be going to' future is used for predictions based on clear and immediate present evidence. 'The way he is driving' is the evidence that strongly suggests an accident is imminent. Option (b) is a more general prediction, less connected to the immediate visual evidence.

**Rule:** The Future Continuous Tense (will be + verb-ing) can describe an action that will happen as part of a planned sequence of events. It describes what will be in progress at the moment the queen arrives. It paints a picture of the future scene. Option (c) means the anthem will already be finished.

**Rule:** The Future Perfect Tense (will have + past participle) is used to express an action that will be completed by a specific point in the future. 'By the time the documentary is over' sets the future deadline by which the action of learning will be complete. Option (c) suggests the learning will be in progress, not finished.

**Rule:** The Future Perfect Tense (will have + past participle) is used to express that a future action will be completed before another future event. The action of finishing the presentation will be done by the time the boss calls. Option (b) implies the action will be in progress at that moment.

**Rule:** The Future Continuous Tense (will be + verb-ing) is used to describe an action that will be in progress at a specific time in the future. 'This time next month' pinpoints the future moment when the action of flying will be happening. Option (d) suggests the flight will be over by that time.

**Rule:** The Future Perfect Passive (will have been + past participle) is required. The action ('open') will be performed on the subject ('bridge'). The action will be completed by a specific future time ('This time next month'). Option (b) is future continuous active. Option (c) is simple present active. Option (d) is simple present passive.

**Rule:** This is a First Conditional sentence (if + simple present, ... will + base verb), used for real or likely future situations. The main clause expresses the future result of the condition. 'will not speak' correctly states the future consequence. Option (b) 'is not speaking' is Present Continuous. Option (c) 'doesn't speak' is Simple Present and grammatically incorrect in the main clause. Option (d) 'would not speak' is used in the Second Conditional for hypothetical situations.