31. Contract is the effect, while the obligation is the cause. 32. D obliged himself to give C P1,000,000 if the latter would not kill X, a third person. In this case, both the condition as well as the obligation are void. 33. In alternative obligation all things are due just like facultative obligation. 34. In a solidary obligation the remission of the whole debt is a donation to all the debtors. 35. In facultative obligation the right to choose can be given to the creditor. 36. A person civily liable is also criminally liable. 37. Every person obliged to give something is also obliged to take care of it with due diligence of a good father of a family always. 38. The creditor has the right to the fruits of the thing from the time the obligation is constituted. 39. An obligation subject to resolutory condition is demandable regardless of the effects of the happening of the event. 40. Payment made by the debtor to a third person who is not the creditor will not extinguish the obligation. 41. Any waiver of an action for future fraud if done voluntarily by the parties is valid. 42. An obligation payable "as soon as possible" is an obligation with a period for the benefit the creditor only. 43. D obliged himself \"to pay C the sum of P50,000 which he owes him when he (D) feels like it ".This kind of obligation is valid and legally enforceable. 44. Solidarity may be presumed just like in joint obligations. 45. Condonation is generally gratuitous. 46. Whoever pays on behalf of the of the debtor with or without his knowledge can compel the creditor to subrogate him. 47. Dation in payment is an exception to the rule on indivisibility of payment. 48. In delegacion, the new debtor's insolvency may revive the original debtor's obligation