Identify the regular verb from the verbs given below:
a. cursed
b. cling
c. cost
d. clung

Hint: A regular verb is a verb which is formed by adding ‘-ed’ or ‘-d’ to it. Some examples are dance-danced, cry-cried, etc. Irregular verbs are verbs which form the past tense in other ways such as run-ran, throw-threw. The past tense is formed by not forming -ed or -d but by changing the base verb.

Complete answer:
Let us look at the given options.
> In the first option, the word is cursed. The base verb is ‘curse’. The past tense of curse is cursed. Therefore the past tense is being formed by adding the suffix -ed. Curse is being written as cursed. She was cursed by the witch. Therefore, cursed in option a is a regular verb.

> Option b is cling. Cling is in the present tense. The past tense of cling is clung. The baby monkey clung to its mother’s arms. The past tense is not being formed by adding -ed. It is an irregular verb and thus, a wrong sentence.

> Option c is cost. The past tense of cost is cost. It is not costed. The word costed does not exist in the English language. It is not a regular verb.

> Option d is clung which is the past tense of cling as already explained above. The word is already in its past tense. It does not have -ed or -d in it. Thus, it is also an irregular verb.

Thus, we can conclude that the only regular verb from the given options is option a, that is, cursed. The correct option is option a.

Note: Regular and irregular verbs can be learnt from many sites on grammar as well as grammar books. If the student knows the past tense of a given word, it can easily be identified whether it is a regular verb or an irregular verb.