1. I can't do the science project myself. It's too difficult?
What does it refer to? #2 or #3?
2. doing the science project myself
3. the science project
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4. I'm going to Tom's house to work on the science project.
5. I'm going to Tom's house to do the science project.
(Are both the same? What is the difference between #4 and #5?)
In #1, "it" would have to refer to the science project. The word "project" is the noun to which the pronoun "it" refers.
http://www.chompchomp.com/terms/antecedent.htm
There's not much difference between 4 and 5. Sentence 4 implies that they may or may not finish the project at that time. Sentence 5 implies that they'll work on it until it's finished.
To determine what "it" refers to in your first statement, we need to understand the context of the conversation or the previous statements. Without that information, we cannot definitively say whether "it" refers to #2 (doing the science project myself) or #3 (the science project). However, based on the most common usage, "it" would likely refer to #2, as it specifically mentions the difficulty of doing the project oneself.
Regarding the difference between #4 and #5, both sentences express the intention of going to Tom's house to work on or do the science project. However, there may be a subtle difference in emphasis.
#4 "I'm going to Tom's house to work on the science project" suggests that the primary purpose of going to Tom's house is to engage in the task of working on the science project. It implies that you will be actively participating in the project alongside Tom.
#5 "I'm going to Tom's house to do the science project" also conveys the intention of working on the science project, but it places slightly more emphasis on the completion of the project itself rather than the process of working on it. It implies that the main objective is to get the project done, with less emphasis on the specific actions taken during the process.
In summary, the difference between #4 and #5 is mainly in the emphasis on the process (working on) versus the outcome (doing) of the science project.