`42.A`

`->` Toxic (adj.): độc hại $\approx$ harmful to our body: có hại cho cơ thể chúng ta

`43.C`

`-` Dẫn chứng: Smoking weakens our lungs as well as other parts of our body. We will not be as active as before and will need more effort to move about.

`44.D` 

`-` Dẫn chứng: Smoking weakens our lungs as well as other parts of our body. 

`45.D`

`-` Dẫn chứng:

`+)` Cigarettes contain toxic substances like tar and nicitine. That is why we often hear people telling us that smoking is harmful to our bodies. 

`+)` Since smoking does not do any good to us, we should always say no to cigarettes. 

`46.B`

`-` Dẫn chứng: We should advise our loved ones to take sweet instead whenever they feel like taking toxic puff.