用磷脂酶C（PLC）处理完整的细胞，能释放出哪一类膜结合蛋白

A.整合蛋白（integral  protein）

B.外周蛋白（peripheral  protein）

C.脂锚定蛋白（lipid-anchored  protein）

D.脂蛋白（lipoprotein）

In a public-key cryptosystem, (71) encrypted with the public key can only be deciphered with the private key from the same (72) . Conversely, (71) encrypted with the private key can be decrypted only with the public key. Users can make their public keys (73) available or place them at a key distribution center or others to access. However, the private key must be (74) safe. In public-key systems there’s no (75) to find a safe channel for communicating a shared secret key.

（74）是（）

A.keep

B.keeped

C.keeping

D.kept