纽

niǔ

knot; button, handle; tie

HSK 6 7 丶

约

yuē

treaty, covenant, agreement

HSK 4 6 丶

证

zhèng

to prove, to verify; certificate, proof

HSK 4 7 丶

券

quàn

bond, certificate, deed; ticket; contract

HSK 6 8 丶

交

jiāo

to connect; to deliver, to exchange; to intersect; to mix

HSK 4 6 丶

易

yì

to change; to exchange, to trade; simple, easy

HSK 3 8 丶

所

suǒ

place, location; "that which", a particle introducing a passive clause

HSK 2 8 丶