Open the leaf to find a caterpillar.
The meaning is finding fault in trivial matters. This is equivalent to “Splitting hairs” (i.e., arguing about unimportant differences) or “Nitpicking” (i.e., finding fault in trivial matters (nits are lice eggs)).
For torn shirts, replace the shoulder, for torn pants, change the pant leg.
This is advice on patching and sewing torn clothes. This is similar to “A stitch in time saves nine” (i.e., one should mend a small tear (or problem) with one stitch before it gets bigger requiring nine stitches (or more effort to fix)).
Ponds have shores, rivers have banks.
The meaning is describing how everything has boundaries and limits and rules should be respected. This is similar to “Toe the line” (i.e., following the rules) or “Draw the line” (i.e., setting a limit that must not be breached).
Who chooses the house door to crawl out.
The meaning is describing circumstances beyond one’s control (e.g., in which house/family to be born) that have to be accepted. This is equivalent to “Like it or lump/leave it,” “What will be will be,” or “In the lap of the gods.”
Weaver girl and cowherd.
The meaning is describing the separation of husband and wife by comparing them to the Cowherd (Ngưu Lang) and the Weaver Girl (Chức Nữ). The Cowherd, symbolizing the star Altair, and the Weaver Girl, symbolizing the star Vega, were banished to opposite sides of the heavenly river (i.e., the Milky Way). Every year, they are only allowed to reunite on the 7th day of the 7th month of the lunar calendar through a bridge formed by a murder of magpies (crows). This is similar to the star-crossed lovers Romeo and Juliet.
With prayer, there is holiness; with forbearance, there is good.
The meaning is advice on good conduct and often a mantra uttered during the 7th lunar month to ward off evil, because the 7th lunar month is linked to Vu Lan Festival or Ghost Festival (Ullambana Festival) (Buddhist origin). This is similar to “Peace be with you” or “God help/bless you” in Christianity.
Beyond three, three times.
The meaning is not to do anything more than three times (i.e., change tactics if one fails thrice). It is a variant of “Sự bất quá tam / Nothing more than thrice.” This is contrasted with “Third time’s a charm,” “Third time lucky,” or “If at first you don’t succeed, try, try again,” which encourages someone to try again after failing already.
Who knows how to shape the hook to fit the fish’s mouth.
The meaning is (i) it is not possible to choose something pleasing to another person and (ii) one cannot know and plan for everything. This is similar to “Hit or miss” (i.e., something unpredictable) or “You cannot please everyone” (i.e., someone will always complain no matter what you do).
Each knows one’s role.
The meaning is (i) each person minds own business and does not interfere with others and (ii) each person has own destiny and does not compare with/should not be jealous of others. A variant is “Voi biết voi, ngựa biết ngựa / Elephants know elephants, horses know horses.” This similar to “To each his own”, “Mind your own beeswax” and “March to the beat of one’s own drum.”
Nine persons ten opinions.
The meaning is describing having many people in charge only makes an activity more complicated. A variant is “Lắm thầy nhiều ma / A lot of exorcists many ghosts” where having many exorcists leads to many ghosts. This is equivalent to “Too many chefs spoil the broth” or “Too many generals, not enough privates.”