New words：

virus [ˈvaɪrəs] n. 病毒

Sample Sentences：

So far they have not found a way to fight the virus.
This software is designed to scan all new files for viruses.
Like the flu virus, a computer virus can spread all over the world.

New words：

bacteria [bækˈtɪriə] n. 细菌（复数）
bacterium [bækˈtɪriəm] n. 细菌（单数）

Sample Sentences：

All bacteria are larger than viruses.
The bacteria are harmless to humans.
Soap destroys the cell walls of bacteria.

virus [ˈvaɪrəs] n. 病毒

New words：

thus [ðʌs] adv. 因此；于是；所以；这样；如此

Sample Sentences：

He studied hard, thus he passed the exam.
The team worked well together, thus winning the game.

Hold the pen thus, and you’ll write better.
The problem can be solved thus, as I showed you.

New words：

global [ˈɡləʊbl] adj. 全球的；全球性的；全世界的

Sample Sentences：

Global travel became easier with planes.
Global warming is a big problem for everyone.
The event attracted global attention last year.

New words：

evolution [ˌiːvəˈluːʃn] n. 演变；进化；发展；渐进

Sample Sentences：

The evolution of basketball rules makes the game safer.
The teacher drew a timeline of the computer’s evolution.
The evolution of humans from apes took millions of years.