verbs: (1) It rains. (2) It is cold. (3) It is growing dark. (4) It seems that there is no end to this. (5) It is unclear why he cut the rope. The expletive pronoun it in these sentences does not denote a clear entity, yet the meaning is clear. In other words, the pronoun it has no clear antecedent. English is so strict about requiring a subject that it supplies them for verbs that do not really require them. In sentences (4) and (5), it is in the subject position, while the real subject has been moved to the end of the sentence. A simple test can be done to see if the sentence contains an impersonal verb. One checks to see if a given subject pronoun takes an antecedent in the previous clause or sentence, e.g. Bukit Timah is 163.63 metres tall. It is the highest point in Singapore. Bukit Timah is 163.63 metres tall. It rains frequently there. The two examples may seem similar, but only the pronoun it in the first example links with the previous subject. The pronoun it in the second example, on the other hand, has no referent. The hill (Bukit Timah) does not rain, it rains. This demonstrates that rain is an impersonal verb. Spanish There is no equivalent of the dummy subject it in Spanish. In Spanish, there are a few true impersonal avalent verbs. Most of them are "atmospheric verbs": llueve It's raining ha helado It froze Most impersonal constructions in Spanish involve using a special verb in third-person defective verb with a direct object as its only argument or use of impersonal se (not to be confused with other uses of se). There are two main impersonal verbs in Spanish: haber (to have, there to be) and hacer (to do). Haber is an irregular verb. When used as an impersonal verb in the present tense, it has a special conjugation for the third person singular (hay). Clauses with the verb haber do not have an explicit subject; its only argument is a direct object noun phrase that does not agree with the verb. Haber has its 'natural meaning' of tener 'to have'. Hay un libro (aquí). There is a book (here) Hay muchos libros. There are many books Hubo muchos libros (que no se vendieron). There were many books (that were not sold). Less frequently, and only in some