I have found the two sentences in Michael Swan's Practical English Usage .(page no 556)

1.This discovery means that we will have to spend less on food.

2 This Discovery will mean that we spend less on food.

It was explained that " if the main verb of a sentence makes it clear that what kind of time the speaker is talking about , it is not necessary for the same time to be indicated again in subordinate clauses"

The author talks about the tenses in the clauses but I could not understand whether the change of the tenses in the main and subordinate clauses changes the meaning of the two sentences given again

I would like to know if both the sentences mean the same thing or do they differ in meaning

I have found the two sentences in Michael Swan's Practical English Usage .(page no 556)

1.This discovery means that we will have to spend less on food.

2 This Discovery will mean that we spend less on food.

It was explained that " if the main verb of a sentence makes it clear that what kind of time the speaker is talking about , it is not necessary for the same time to be indicated again in subordinate clauses"

The author talks about the tenses in the clauses but I could not understand whether the change of the tenses in the main and subordinate clauses changes the meaning of the two sentences given above

I would like to know if both the sentences mean the same thing or do they differ in meaning

I have found the two sentences in Michael Swan's Practical English Usage .(page no 556)

1.This discovery means that we will have to spend less on food.

2 This Discovery will mean that we spend less on food.

It was explained that " if the main verb of a sentence makes it clear that what kind of time the speaker is talking about , it is not necessary necessary for the same time to be indicated again in subordinate clauses"

The author talks about the tenses in the clauses but I could not understand whether the change of the tenses in the main and subordinate clauses changes the meaning of the two sentences given again

I would like to know if both the sentences mean the same thing or do they differ in meaning

I have found the two sentences in Michael Swan's Practical English Usage .(page no 556)

1.This discovery means that we will have to spend less on food.

2 This Discovery will mean that we spend less on food.

It was explained that " if the main verb of a sentence makes it clear that what kind of time the speaker is talking about , it is not necessary for the same time to be indicated again in subordinate clauses"

The author talks about the tenses in the clauses but I could not understand whether the change of the tenses in the main and subordinate clauses changes the meaning of the two sentences given again

I would like to know if both the sentences mean the same thing or do they differ in meaning