Task: Text Completion
Input (English): [header] How to lay a porcelain tile exterior patio [title] Use a bonded cement/sand screed to level the concrete substrate if necessary. [step] To avoid problems with the screed shrinking (and causing the tiles to crack), allow it to dry out for 1 to 2 weeks. For minor surface irregularities simply use a levelling compound. <sep> (A) The screed must be pre-applied by a professional. For larger trenches, applying compound prior to construction would make the process safer but still have to be applied. (B) Do not let the cement dry out too long. Concrete in concrete potting beds can be treated professionally. (C) [title] Ensure the surface that you are laying the porcelain tiles on is as level as possible, clean and dry, and remove any loose particles. [title] Select a " thin bed " adhesive for very flat surfaces with level differences of no more than 6 mm. (D) Make sure there is no wind, or that it is not windy. It is important that these deposits settle sufficiently so that the pre-treated area is dry, although delicate the concrete lime (water from the tap) absorbs moisture quickly.
Output (English): C