Hi, Alex! We use "extend" when we are talking about increasing something in a linear way, whereas "expand" is used to mean increasing in multiple directions and/or ways. Here are two examples: "I asked my teacher to extend the due date she originally set for our assignment." In this sentence, I only want the time I have to do the assignment increased, so I'm using "extend." "The general vastly expanded his empire's territory within a month." In this sentence, the increase is happening in multiple directions, so we use "expand." In your sentence, because the delivery time is linear, you would use "extend." If you were discussing increasing the number of locations that your delivery service wanted to cover, you would use "expand." I hope my answer helps. Please let me know if you still have any questions.

Hi Alex, When something "expands", it takes up more space or increases in its volume. When something "extends", it becomes longer than its original length. Examples: A liquid gains heat and expands while a load hung on a spring causes it to extend. Generally, "Expand" means to spread out; "Extend" means to stretch out or lengthen something. Having said so, the difference between these two words is not as simple as the direction of movement of something. (Refer to **) Both words are also used in other different contexts. Expand: 1) We can "expand" a business into other sectors. In this case, we are making our business more extensive. (In this context, we are trying to increase the scope of a business.) 2) We may "expand" an investigation or explanation. (In this case, we are trying to elaborate or gather more details on a matter.) 3) A bird which "expands" its wings unfolds them. Extend: 1) We "extend" the length of our vacation by deciding to stay a few more days. (In this case, we prolong the duration of an activity.) 2) We "extend" our hands to offer someone a handshake. (In this case, we are jutting our hand towards someone to offer a friendly gesture.) 3) We can "extend" the mobile coverage of a city. (In this case, we are stretching out something in all directions.) ** Notice that the word "extend" describes a radial movement instead of a unidirectional movement. Example: As our business "expands", we will "extend" our operating hours! Back to your sentence: It needs to "extend" delivery time. (Since we are referring to lengthening the duration of an activity.) Hope this helps. Cheers, Lance

It needs to extend delivery time is good. Extend means to make something longer, and is often used with time. Expand means to make something bigger, which is different to longer. Another verb you could use is to stall (to slow down).

It should be extend. Expand is increase in size, become larger, enlarge. Extend is the word you need :)

Hi Alex, you can find a good explanation here: https://www.dailywritingtips.com/expanded-and-extended/