הגשר יכול לשאת הרבה מכוניות.

ה־ is the Hebrew definite article, equivalent to English the. Hebrew usually attaches it directly to the noun.

So:

• גשר = bridge
• הגשר = the bridge

Because גשר is a masculine singular noun, and יכול agrees with the subject in gender and number.

So:

• הגשר יכול... = the bridge can...
• המכונית יכולה... = the car can...
• הגשרים יכולים... = the bridges can...

Even though a bridge is not a person, Hebrew still gives it grammatical gender.

In everyday Hebrew, yes. יכול literally means able / capable, but it is very commonly used the way English uses can.

A very common pattern is:

subject + יכול + infinitive

So:

• הוא יכול לבוא = he can come
• הגשר יכול לשאת... = the bridge can carry / support...

After יכול, Hebrew uses the infinitive, and Hebrew infinitives normally begin with ל־.

So לשאת means to carry / to bear.

Even though English drops to after can, Hebrew still uses the infinitive form:

• יכול לשאת = literally something like able to carry
• but in normal English translation: can carry

Here לשאת means to bear, carry, support.

With a bridge, the idea is usually supporting weight, not physically transporting cars somewhere. So in this sentence it is closer to:

• bear
• support
• carry the load of

It comes from the root נ-ש-א, and this verb is somewhat irregular, so the infinitive לשאת may not look very obvious at first.

Because את is used before a definite direct object, and הרבה מכוניות is indefinite: it means many cars, not the cars.

Compare:

• הגשר יכול לשאת הרבה מכוניות = The bridge can support many cars
• הגשר יכול לשאת את המכוניות = The bridge can support the cars

So no את is needed here.

Yes, both are correct.

• הרבה מכוניות = the most common everyday way to say many cars
• מכוניות רבות = also correct, but often feels a bit more formal or literary

A useful thing to notice:

• הרבה does not change here
• רבות does agree with מכוניות, so it appears in the feminine plural form

The singular is מכונית, meaning car.

It is a feminine noun, and its plural is מכוניות.

So:

• מכונית = car
• מכוניות = cars

The ending ־ות is a very common feminine plural ending in Hebrew.

Yes. This is a very normal structure:

subject + יכול + infinitive + object

So in this sentence:

• הגשר = subject
• יכול = can / is able
• לשאת = to carry / support
• הרבה מכוניות = object

In this case, the word order is actually quite close to English, which makes the sentence easier for English speakers to follow.