"Do you like summer?" and "You like summer." are translated respectively as and (There is not always a difference between the wording of a yes–no question and the corresponding statement in Spanish.) These new rules were slowly adopted; there are 19th-century books in which the writer uses neither "¡" nor "¿". In sentences that are both declarative and interrogative, the clause that asks a question is isolated with the starting-symbol inverted question mark, for example: ("If you cannot go with them, would you like to go with us?"), not   Some writers omit the inverted question mark in the case of a short unambiguous question such as: ("Who comes?"). This is the criterion in Galician and Catalan. Certain Catalan-language authorities, such as Joan Solà i Cortassa, insist that both the opening and closing question marks be used for clarity. Some Spanish-language writers, among them Nobel laureate Pablo Neruda (1904–1973), refuse to use the inverted question mark. It is common in Internet chat rooms and instant messaging now to use only the single "?" as an ending symbol for a question, since it saves typing time. Multiple closing symbols are used for emphasis: , instead of the standard ("Why do you say that?"). Some may also use the ending symbol for both beginning and ending, giving Given the informal setting, this might be unimportant; however, teachers see this as a problem, fearing and claiming that contemporary young students are inappropriately and incorrectly extending the practice to academic homework and essays. (See )  In 1668, John Wilkins proposed using the inverted exclamation mark "¡" as a symbol at the end of a sentence to denote irony. He was one of many, including Desiderius Erasmus, who felt there was a need for such a punctuation mark, but Wilkins' proposal, as was true of the other attempts, failed to take hold. It is acceptable in Spanish to begin a sentence with an opening inverted exclamation mark ("¡") and end it with a question mark ("?"), or vice versa, for statements that are questions but also have a clear sense of exclamation or surprise such as: ("And who do you think you are?!"). Normally, four signs are used, always with one type in the outer side and the other in the inner side (nested) (', ')  Unicode 5.1 also includes , which is an inverted version of the interrobang (also known as a "gnaborretni" ()), a nonstandard punctuation mark used to denote both excitement and a question in just one glyph.   and are both located within the Unicode Common block, and are both inherited from ISO-8859-1, as and , respectively.    and are available in all keyboard layouts for Spanish-speaking countries.