**Rule:** The Future Simple Passive ('will be' + past participle) is used to state a future fact or a planned outcome. 'will be completed' is the correct passive form. Option (d) 'will have been' would also fit, but 'will be' is a more direct and common way to state the future completion date.

**Rule:** The Simple Future with 'will' is used here to make a promise for a future action, decided at the moment of speaking. The speaker spontaneously decides to think and then inform. Option (d) would suggest a prior intention to think, which is less fitting for this context.

**Rule:** The Future Continuous Tense (will be + verb-ing) is used to talk about an action that will be in progress over a period of time in the future. The context implies that the act of studying will be ongoing during the time of the party. Option (a) 'will study' is a general future statement. Option (b) 'will have been studying' (Future Perfect Continuous) would require a duration (e.g., 'for three hours'). Option (d) 'study' is the simple present and incorrect for a future continuous action.

**Rule:** The Present Continuous Tense ('is/are' + verb-ing) can be used to talk about definite plans or arrangements for the future. Introducing new regulations is a planned government action. Option (a) 'introduces' would be used for a scheduled, repeated event, not a one-time plan. Options (c) and (d) are incorrect tenses.

**Rule:** This question tests tense consistency. The reason for the present situation ('We can't get a table') is a past action (or lack thereof). The failure to make a reservation happened in the past. Therefore, the Simple Past Tense ('didn't make') is required. The other options refer to the future, which doesn't explain the current problem.

**Rule:** The Simple Future with 'will' is the most common tense used for making general, long-term predictions about the future. This is a prediction about a distant future state. Option (b) is also possible for predictions, but 'will' is standard for these broad, speculative statements. Options (a) and (c) are incorrect.

**Rule:** The Simple Present Tense is the standard choice for future events on a fixed schedule or program. A performance start time is a scheduled event. Both (a) and (b) are very common, but simple present is often preferred for official, timetabled events.

**Rule:** 'Be going to' is used to express a future plan or intention that has already been decided. The phrase 'I've decided' clearly indicates a prior intention. Option (a) 'will use' is for a decision made at the moment of speaking, which contradicts 'I've decided'. Options (c) and (d) are incorrect.

**Rule:** The 'be going to' form is used to talk about a prior plan or intention. The phrase 'I've decided' clearly indicates that the decision was made before the moment of speaking. Option (a) 'will buy' is used for spontaneous decisions, which contradicts 'I've decided'. Options (b) and (d) are incorrect in this context of expressing a prior intention.

**Rule:** The Future Perfect Tense (will have + past participle) is used to express that an action will be completed by a specific future deadline. 'By the end of the day' is the deadline by which the action of interviewing all candidates will be finished. Option (c) implies the action will be in progress at that time.