**Rule:** The Simple Future with 'will' is used for making promises. The speaker is promising to call in the future. The time clause 'as soon as I have any news' correctly uses the simple present. Option (d) is for prior plans, but this sounds more like a promise made now.

**Rule:** When asking about future events that are part of a fixed schedule or timetable, it is common to use the Simple Present Tense. The structure is 'What time does [subject] start?'. Option (c) 'is...starting' is also very common and correct for asking about future arrangements. Option (b) is future continuous. Option (d) is future perfect.

**Rule:** Both Simple Present ('leaves') and Present Continuous ('is leaving') can be used for future events that are part of a fixed schedule or timetable. The simple present is very common for transport schedules. Present continuous is also correct as it refers to a fixed personal arrangement. However, for official timetables, simple present is the most standard choice.

**Rule:** The Simple Future with 'will' is used to express an opinion, belief, or prediction, especially after verbs like 'I think'. The speaker is giving their opinion on a future appearance. Option (c) is also possible, but 'will' is the most common choice for expressing such personal opinions.

**Rule:** The Simple Future with 'will' is used to express beliefs or predictions about the future, especially distant ones. It's the standard choice after verbs like 'believe', 'think', and 'expect'. Option (c) is also for predictions but often based on more immediate evidence. Option (a) is present continuous. Option (d) is future perfect.

**Rule:** The Future Continuous Tense (will be + verb-ing) can be used to talk about planned future events, similar to the Present Continuous. It suggests that the exhibition is a confirmed plan. Both 'is exhibiting' and 'will be exhibiting' are correct for future plans, but the latter is offered as an option here. Option (a) is for schedules, which is less likely for an art exhibition. Option (c) is past tense.

**Rule:** The Present Continuous Tense ('is/are' + verb-ing) is used to talk about definite future plans and arrangements. A politician's campaign is a planned series of events. 'is going to run' would also be correct. Option (b) is for habits. Option (c) is future perfect. Option (d) is past.

**Rule:** The Future Continuous Tense (will be + verb-ing) is often used to ask about someone's plans for a specific future time in a polite and indirect way. It's less direct than asking 'Are you going to watch?'. Option (d) is future perfect. Options (b) and (c) are incorrect tenses.

**Rule:** The 'be going to' future is used to express a plan or intention that has already been decided. The fact that 'she's been practicing all week' is strong evidence of her prior intention to audition. Option (b) 'will audition' would suggest a spontaneous decision. Option (a) 'auditions' is the simple present, used for habits or schedules, which doesn't fit here. Option (d) 'will have auditioned' is the future perfect, indicating completion before a future point, which is not the intended meaning.

**Rule:** In conditional clauses beginning with 'unless' (which means 'if...not'), the Simple Present Tense is used to refer to a future condition. The main clause uses a future tense. Option (a) 'will work' is incorrect in the conditional clause. Option (c) 'are working' is the present continuous. Option (d) 'don't work' would create a double negative ('Unless you don't work' means 'If you work'), changing the meaning.