How do you know when to use "qué" and "cuál" when asking a question in Spanish?
Both "qué" and "cuál" can be translated as "what" in English. For example, "¿Qué hora es?" translates as "What time is it?", and "¿Cuál es tu nombre?" translates as "What is your name?". However, their use slightly differs, and they are not usually interchangeable. - "Qué" is normally used when asking a question that has one possible answer, such as a definition, fact or information about something that's generally well-know. "¿Qué es la salsa?" (What is salsa?) "¿Qué colores tiene la bandera de Francia?" (What colours are in the French flag?) "¿Qué te ha dicho el médico?" (What did the doctor tell you?) - "Cuál" is used when the question involves a selection or personal information. "¿Cuál es tu animal favorito?" (What is your favorite animal?) "¿Cuál es el mejor hotel en Madrid?" (What is the best hotel in Madrid?) If the object of the sentence is plural, then "cuál" will be substituted by its plural form "cuáles". "¿Cuáles son los países más ricos?" (What are the richest countries?) * In some cases, "qué" and "cuál" can also be translated as "which" or "which one". "¿Qué restaurante prefieres?" (Which restaurant do you prefer?) "¿Cuál de ellos es tu amigo?" (Which one of them is your friend?)
What is an atom composed of?
An atom is composed of three different subatomic particles: protons, neutrons and electrons. Protons and neutrons stick together in a cluster known as the nucleus, which acts as the center of the atom. For a given atom, protons and neutrons have the same mass, and, while protons have a positive charge, neutrons have no charge. The number of protons in an atom, which may vary from one up to the hundreds, is its atomic number, which is characteristic of a chemical element and determines its place in the periodic table. The combined number of protons and neutrons in an atom is its mass number, which differentiates multiple forms, or isotopes, of the same chemical element. Electrons have negative charge and a very small mass, often negligible compared that of protons and neutrons. They have a negative charge and orbit around the nucleus in defined orbitals. As opposed to protons and neutrons, which may be divided into more subparticles, electrons are elementary particles, and they can behave both as particles and energy waves.
When should I use the infinitive and the gerund of a verb?
First of all, a definition: An infinitive is the basic form of a verb, TO + VERB, as in "to go". A gerund is a verb in its present participle form, VERB + ING, as in "going". Both can act as a noun in a sentence, as in "I like reading" or "Do you want to jump?", but they can never be the main verb (e.g. "I reading" or "Do you to jump?" are incorrect). It is common for them to be followed by a second noun (e.g. "I like reading books"), since they are still verbal forms and involve an action. There are a few basic rules to know when to use infinitives and gerunds. There are always exceptions to the rules, but these are almost always true. - If you're looking for an action as a SUBJECT, use a GERUND: "Playing football is fun" "Cooking can be very difficult" - After a PREPOSITION, use a GERUND: "She was tired after running the race" "I thought about going to the party" - After an ADJECTIVE, use an INFINITIVE: "It is hard to concentrate in class" "Good strawberries are hard to find" - After a NOUN, use an INFINITIVE: "Do you want me to drive?" "She called her sister to ask about her exam" - After a VERB, it depends. There is a list of verbs who take a GERUND (advise, avoid, enjoy, finish, practice, quit, suggest, etc.), others take an INFINITIVE (ask, choose, decide, get, need, plan, promise, want, etc.) and some can use EITHER (like, love, hate, etc.): "They enjoy skiing in the winter" "When did you decide to get married?" "I like playing tennis" / "I like to play tennis" * It is also worth remembering that BE + -ING VERB can also be a progressive verb form, and and that -ING adjectives are possible after the be verb or before a noun: "I am making dinner" (present progressive verb, not a gerund) "The movie was boring" (adjective, not a gerund) "That was a boring movie" (adjective, not a gerund)