拋磚引玉 in english (20 points)

字面譯:
Casting a brick to draw in a jade.
(of writing): offer my crude opinion in the hope that it will draw forth more valuable views by others.
英文相關成語:
(原句) "a sprat to catch a mackerel".
People usually add "Throw" ; or "Throw out" before it.
Throw (out) a sprat(西鯡-à一種細小魚) to catch a mackerel.(鯖魚)
(變體)Throw out a minnow to catch a whale.
Or:
Venture a small fish to catch a great one.

Idiom
拋磚引玉to throw a brick to attract jade

可以用英文俚語:
To throw out a minnow to catch a whale

minnow = 鯉科小魚
whale = 鯨魚