(1)Once the lecture starts:let your mind dart (2)ahead during pauses to anticipate what is next.

(1)
a) No change
b)Once the lecture starts, let your mind
c)Once the lecture starts; let your mind

I chose b)

(2)
a)no change
b)ahead (during pauses)
c)ahead, during pauses
d)ahead during pauses,

On this one I chose answer a)no change

Now I'm thinking maybe I should have chosen b) ?

Right the first time >> b and a

wonderful --thanks ; )

Both answers (a) and (b) for sentence (2) are acceptable, so your choice of answer a) is correct. The phrase "during pauses" is optional and can be placed either after "ahead" (as in answer a) or within the parentheses (as in answer b). Both options are grammatically correct, so you made the right choice.

To determine if your choices are correct or not, let's reason through the options:

(1) The original statement is "Once the lecture starts: let your mind dart". This usage of the colon suggests that what follows is an explanation or a continuation of the preceding phrase. However, in this case, it seems like there is a list, so using a colon may not be appropriate.

a) No change: This option keeps the colon, so it may not be the best choice here.

b) Once the lecture starts, let your mind: This option adds a comma after "starts" and replaces the colon with a comma, which improves the readability. This option seems more appropriate for this sentence.

c) Once the lecture starts; let your mind: This option replaces the colon with a semicolon, which indicates a stronger separation than a comma. Although it's grammatically correct, it may not be the best choice for this sentence as it implies a stronger break in the flow.

Based on this analysis, b) Once the lecture starts, let your mind seems to be the most appropriate choice.

(2) The original statement is "ahead during pauses to anticipate what is next". This part seems concise and clear, but let's look at the options.

a) No change: This option keeps the original wording, which is grammatically correct and clear.

b) ahead (during pauses): This option adds parentheses around "during pauses". It clarifies that the action of going ahead is done specifically during pauses. This choice provides additional clarity and is a valid option.

c) ahead, during pauses: This option adds a comma before "during pauses". It indicates a slight pause but doesn't provide as clear a distinction as the parentheses. Although it doesn't necessarily change the meaning, it may not be the best choice.

d) ahead during pauses,: This option adds a comma after "pauses", which disrupts the flow of the sentence and is incorrect.

Based on this analysis, both a) No change and b) ahead (during pauses) seem acceptable options. Your initial choice of a) seems to be correct, but b) could also be a valid alternative.