Know When to Use The Past with The Present

One verb tense problem that is common both in student writing and on the TOEFL test is the switch from the past tense to the present for no particular reason. Often when a sentence has both a past tense and a present tense, the sentences is incorrect.

He took the money when he wants it

This sentences says that he took money (in the past) when he wants it (in the present). This meaning doesn’t make any sense (not logic). It’s impossible to do something in the past as a result of something you want in the present. This sentence can be corrected in several ways, depanding on the desire meaning.

He took the money when he wanted it

He takes the money when he wants it.

The first example means that he took the money (in the past) when he want it (in the past). This meaning is logical and the sentences is correct. The second example means that he takes the money (habitually) when he wants it (habitually). This meaning is also logical, and the second example is also correct.

It’s necessary to point out. However, that is possible for a logical sentence in English to have both the past and the present tense.

I know that he took money yesterday

The meaning of this sentence is logical. I know (right now, in the present) that he took the money (yesterday, in the past). You can see from this example that it is possible for an English sentence to have both the past and the present tense. The error you need to avoid is the switch from the past to present for no particular reason. Therefore, when you see a sentence on TOEFL test with both the past and the present tense, you must check the meaning of the sentence carefully to see if it is logical in English.

Conclusion

1.     If you see a sentence with one verb in the past and one verb in the present, the sentence is probably incorrect.

2.      However, it is possible for a correct sentence to have both pasr and present together.

3.      If you see the past and present together, you must check the meaning to determine wheather or not the sentence is correct. 

Source : 10th Meeting Toefl Preparation