Olympics preview

(Coverage on Ch. 4, unless noted)

Gymnastics

Three-time world all-around champion Simone Biles leads the heavily favored U.S. women in their pursuit of a second consecutive gold medal in the finals of team competition. 8 p.m.-midnight

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Swimming

Wonderkind Katie Ledecky goes for gold in the women’s 200-meter freestyle, while the U.S. men’s team competes for a fourth consecutive gold medal in the 4x200 free relay. Also, Michael Phelps is back in the pool in the 200 butterfly final. 8 p.m.-midnight

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Volleyball

The U.S. men’s team meets 2012 Olympic bronze medalist Italy in a preliminary-round matchup.

2 p.m.

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Basketball

Spain, led by Pau Gasol, faces host nation Brazil, which has not won a basketball medal in five decades. Spain has been runner-up to the U.S. in the past two Olympics.

1 p.m., NBCSN, Basketball Specialty Channel

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Rugby

The start of men’s qualifying play begins now featuring 12 teams. The U.S., led by Zack Test, Perry Baker and Carlin Isles, opens vs. Argentina. Rugby is back in the Olympics for the first time since 1924.

9 a.m., NBCSN; 2:30 p.m., USA

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Tomorrow’s best bet

Swimming

The glamor event in the pool: the men’s 100-meter freestyle features 2012 gold medalist Nathan Adrian of the U.S. against Australian star Cameron McEvoy.

8 p.m.-midnight