That

Hi, marcofabri,

@marcofabri posted:

1-Before the Covid-19 pandemic, data from 122 countries indicated that on average, 31.1% of adults are physically inactive and over 80% of adolescents perform less than 60 min of daily physical activities.

You cannot omit "that" there because you have a sentence adverbial, which is "on average." With a slight change whereby the content clause follows the reporting verb "indicated" immediately, without the interference of an insert, you could omit "that":

1.a. Before the Covid-19 pandemic, data from 122 countries indicated an average 31.1% of adults are physically inactive and over 80% of adolescents perform less than 60 minutes of daily physical activities.

@marcofabri posted:

2-  Time-efficient exercise programs that counteract physical inactivity, especially after the Covid-19 pandemic, are a recent major topic of investigation.

You need "that" above because it functions as the subject within the relative clause.

Thank you Gustavo.

In the sentence that you wrote I thought that "of" would be necessary. Can I omit too ?

"Before the Covid-19 pandemic, data from 122 countries indicated an average of 31.1% of adults are physically inactive and over 80% of adolescents perform less than 60 minutes of daily physical activities."

@marcofabri posted:

In the sentence that you wrote I thought that "of" would be necessary. Can I omit too ?

"Before the Covid-19 pandemic, data from 122 countries indicated an average of 31.1% of adults are physically inactive and over 80% of adolescents perform less than 60 minutes of daily physical activities."

"An average of" is a noun phrase, but you can use the adjective "average" before a noun phrase to modify it. You might find this related thread of interest.

Great!

Thanks.