The democratic movement had better ______ on the immediate issues of the economy and security.

- প্রদত্ত প্রশ্নের সঠিক উত্তর হচ্ছে concentrate.

• The democratic movement had better concentrate on the immediate issues of the economy and security.
- এখানে had better হচ্ছে modal auxiliary verb.
- modal auxiliary verb 'Had better' এর পর verb এর base form বসে।
• structure:
- subject + had better/should/ought to/be supposed to + verb in simple form.

Source: Cliffs TOEFL.