Most often with the prefix half-in/half - begin nouns. Most of them have cursive writing, but spelling mistakes in such cases are very often even among those who have the Russian language in the school was a solid "five".
So, just remember the simple rules governing continuous writing.
Together with the prefix half-in/half - written words, the second of which begins with a consonant. In order to better memorize this rule, note that almost all such words – nouns in the genitive form: half past three, pontarelli, bolandrina, half rounds, half-day, postolowo, pontarelli, half an hour, half a second, half a minute, six months, two weeks, half a week, half a million, five hundred, a fifty, a century and a half (hours), etc. the Examples are endless. Keep in mind that the names of the numerals (half past two, half past one, half past twelve, half past three, half past four, half past five, half past six, half past seven, half past eight, etc.) are always written as one word with the prefix Pol-.
As for the prefix semi-, all the words with her always are written together: semiannual, fortnightly, half-hour, semester, etc.
Separate writing of words starting with floors-, is rarer than fusion, but there are two rules that reglamentary that is the spelling. The first rule States that when a half - word is another part of speech (adjective or pronoun), such words are always written separately. For example: half of your Apple, floor, field, floor interesting book, Paul glass cups, half a teaspoon, half tablespoon. The second rule says spelling with the word half, which is also separate: the third half, half an Apple, half apricot, five and a half inches.
Writing with a hyphen
In order to know in what cases you must write the words with a half - hyphenated, you must remember three cases.
The first case is when the word begins with a vowel: a half-apricots, half-oval, half butterscotch, half yard, half-lunch, half-tree, half blackberries, etc.
The second case is when half precedes a proper name, e.g. the name of the city: half of Moscow, half of Kaliningrad, half of Murmansk, a half-Baikal, etc.
The third case is when half precedes a word beginning with the letter "l": half-liter, half spoon, half a lemon, half a bulb.