QUESTION: Can we use through and by to mean the same thing when we’re talking about time?
ANSWER: No. Consider the following three examples:
Example 1: Their project will continue through the winter.
Example 2: Their project will be completed by winter.
Example 3: Their project will be completed by the end of winter.
Examples 1 and 2 are clearly different in meaning. The first means their project will continue during the winter. The second means their project will be completed before winter. Examples 1 and 3 are closer in meaning, yet still remain different. Example 3 is firm about the project coming to its completion at some point before the end of winter. Example 1 fails to specify any information about completion. At most, there may only be an implied idea that the project will be completed around springtime.
Confusion between through and by is rather easy to settle. However, when one starts to explore the various ways we can express duration, distinctions become less clear. In fact, it seems English offers a number of ways to express the same concept of time. Would you agree that the statements within the two following sets are synonymous?
Their project will be completed by winter.
Their project will be completed before winter.
Their project will be completed at some point between now and the start of winter.
They have until December 1.
They have up to December 1.
They have between now and December 1.
They have from now to December 1.
Do you see any differences between the statements in Set B and the statements in the following Set C?
Set C =
They must finish by December 1.
They must finish before December 1.
Perhaps differences between Sets B and C only exist in register, if not in meaning. Generally, the more abbreviated the grammar, the more informal a statement is. The statements in Set B all answer the unspoken question how much time do they have to finish or to take action? In contrast, the statements in Set C are more explicit. Can we conclude that Set B is more idiomatic and therefore less appropriate in formal English?
In other cases, grammar isn’t abbreviated, but a difference in register is commonly perceived:
“May I have more time to finish my work?”
Example 4: I’ll give you until Friday.
Example 5: I’ll give you to Friday. *
“Did you sleep well?”
Example 6: No, I couldn’t fall asleep until 1 or 2 in the morning.
Example 7: No, I couldn’t fall asleep till 1 or 2 in the morning. *
*Examples 5 and 7 sound fine to my ears, but a number of sources would likely view these uses of to and till as appropriate for informal spoken English only.
When it comes to having so many structures that can all perform the same job, students may begin to question the value of learning all of them. I’ve argued in favor of variety before, and I’ll do so again now: As students become more advanced, they must embrace variations rather than avoid them. Skillful communication is characterized by having variety in structure, and the understanding of nuances in meaning, register, or another aspect increases the accuracy and effectiveness of a communicator.