Please explain how to use the modal verbs!

[pioneer]

Test No. incompl/elem-16 "Learn it by heart", question 3

I think learning ......... be interesting because otherwise you wouldn't ever be able to succeed.

(a) can
(b) should
(c) must to

Test No. incompl/elem-16 "Learn it by heart", answer 3

I think learning should be interesting because otherwise you wouldn't ever be able to succeed.

Correct answer: (b) should

Hello dear Alan and Torsten! Why in this test do you choose "should to" To my mind all 3 answer are appropriate.

* * * * * * * * * * * *

Test No. incompl/elem-16 "Learn it by heart", question 9

As of now we still don't know if we will be ......... to fulfil our contract.

(a) reliable
(b) able
(c) capable

Test No. incompl/elem-16 "Learn it by heart", answer 9

As of now we still don't know if we will be able to fulfil our contract.

Correct answer: (b) able

Why in answer 9 I cannot use word "capable"?
Thank you
Pioneer

[Torsten]

Dear Pioneer,

Let's have a look at the question you are referring to:

I think learning ..... be interesting because otherwise you wouldn't ever be able to succeed.

(a) can
(b) should
(c) must to

You certainly agree, that only answer (b) - 'should' is correct here.

Now, on to the second sentence you mentioned:

As of now we still don't know if we will be ..... fulfil our contract.

(a) reliable
(b) able
(c) capable

Here, only answer (b) - 'able to fulfil our contract' is correct as 'capable' is followed by a gerund, so the sentence would have to read '.... if we will be capable of fulfilling our contract.'

Let me know if this makes sense to you. Thanks.
_________________
Test Of English for International Communication
TOEIC Preparation & TOEIC Vocabulary

[pioneer]

Hello dear Torsten again, it really very helped me.
Thank you
Pioneer