-"ce" is the masculine form of "this". (example: ce crayon= this pencil) -"cette" is the feminine form of "this" (example: cette chaise= this chair. -"cet" is a masculine form of "this" that is only used when it comes before a word that begins with a vowel sound. For example, "hibou" (pronounced eeboo) is a masculine word that begins with a vowel sound, therefore "this owl" would translate to "cet hibou". -"ça" = "that". (Example: Ça c'est un bon idée= that's a good idea) -"ces"= "these" (example: "ces choses" = these things). "Ces" is only used when the noun being described is plural, such as "things". I am not quite sure how to answer your second question. I hope this helps!

In French, there is only one type of demontrative determiners. And it's always "ce/cet" (masculine singular), "cette" (feminine singular) and "ces" (plurial). These words all translate "this/these" and "that/those". If you want to specify that it is "THIS" and not "THAT" you need to complement with "-ci", respectively "-là", after the noun, e.g. "ce livre-ci" (this book) vs. "ce livre-là" (that book). But more and more people don't make this distinction except when both "ci" and "ça" appear in the same sentence. Aurélie is right, we don't say "cet hibou" because there's actually a kind of consonant there (glotal stop) although not really considered a French sound. "Ce hibou" is correct. There are few words in this situation and they begin with an H except "un" and any vowel of the alphabet when taking as a noun, e.g. "ce 'a' ne se prononce pas". "ça" doesn't really translate "that". It can also mean "this". BUT not as a determiner, only as a PRONOUN. "ça" is the colloquial version of "cela".