Tomorrow the President ' is going open a new hospital '

Explanation of all the options:

1.is going open a new hospital

• Explanation: This option is missing the preposition "to." The correct structure should be "is going to open."
• Incorrect ❌

2.will going open a new hospital

• Explanation: This option is incorrect because "will" cannot be followed by "going." It mixes future tense constructions incorrectly.
• Incorrect ❌

3.is going to open a new hospital

• Explanation: This option is correct. It uses the future construction "is going to" appropriately to indicate a planned action.
• Correct ✅

4.will going to open a new hospital

• Explanation: This option is incorrect for the same reason as option 2. The combination of "will" and "going to" is grammatically incorrect.
• Incorrect ❌

5.will go to open a new hospital

• Explanation: This option is grammatically correct, but it suggests that the President will travel to the location of the hospital to open it, rather than indicating a plan to open it. It does not convey the same intended meaning as the original sentence.
• Incorrect ❌