Although people enjoyed reading his book，many of them thought that Marco's stories about China were too fantastic to be true.
虽然人们爱读马可的书，但许多人认为他书中关于中国的描述太离奇而不可信。
Bacteria are

too small to be seen

too small to be seen

by the naked eye.
细菌太小，肉眼是看不见的。